Human Anatomy-Physiology and Yoga

An attempt to understand how ancient science of Yoga helps boost immunity, maintain health and prevent/cure diseases.

What is health?

Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. – World Health Organization

Human Organism

Human Organism -> Systems -> Organs -> Tissues -> Cells -> Molecules -> Atoms -> energy

Chemical level – Atoms and molecules Important Biological Molecules

  • Carbohydrates
  • Proteins
  • Lipids
  • Enzymes

Cellular system

Cell is the structural and functional unit of human organism. Human body develops from a single cell, which results from a fusion of ovum (female egg cell) and sperm (male germ cell). As fetus grows cell multiplication takes place and cells with different structural and functional specializations develops, every thing from the same genetic code.

A cell consists of a membrane inside which there are several organelles floating in the intracellular fluid called cytoplasm.

  • Cell membrane

Encloses every human cell, permeability of cell membrane allows nutrients to go in, and waste material to go out. This is also first line of defense which protects intraceliular environment from any potential form of pathogen, bacteria or viruses.

  • Cytoplasm Intracellular fluid
  • Organelles They include Nucleus, Mitochondria, Ribosomes, Endoplasmic reticulum, Golgi apparatus, lysosomes etc.
  • Nucleus

Every cell in the body has a nucleus; Red blood cell is an exception. It is on of the largest organelle. The nucleus contains genetic material of the body, which directs the activities of cell. Genetic material is built from DNA (Deoxyribonucleic acid)

  • Mitochondria

It is described as powerhouse of the cell, process of cellular respiration takes place here and that releases chemical energy called ATP (Adenosine tri phosphate) that is needed as primary energy source for different cellular activities.

  • Ribosomes

They synthesize protein from amino acid, using RNA (Ribonucleic acid). Protein produced by Ribosomes is used with in the cell.

  • Endopiasmic reticulum

There are two types of Endoplasmic reticulum, smooth and rough. Smooth ER synthesizes lipids and steroids hormones. Rough ER synthesizes proteins that are exported to other cells of the body, i.e. enzymes and hormones.

  • Golgi apparatus

It is present in all the cells but larger in those that synthesizes and export proteins. Proteins move from endoplasmic reticulum to the Golgi apparatus for packaging and to be ready to go to the cell membrane, through which the proteins are exported.

  • Lysosomes

They contain variety of enzymes involved in breaking down fragments of organelles and large molecules (e.g. DNA, RNA, carbohydrates, proteins etc.) inside the cells, to be used, recycled or extruded from the cell as waste.

Life span of Cell

Life span of the cell depends upon the types for example Red blood cell – 120 days

White blood cell -1 month to a year

Platelets – 10 days

Skin cells – few weeks to month

Bone cell – 20 to 25 years

Nerve cell – equals to the life span of organism etc.

Stress and Cell

Cells are exposed to the stress all the time, due to the potential of adaptation cells are able to cop stress and become stronger to face new challenges. It works line as long as the stress is momentary but the problem starts occurring when it continuous.

Continuous stress means over work of the cell, leads to fatigue and early death of the cell before completing the normal life span.

To break the continuous stress nature has provided a gift to every human being as deep sleep, which not only breaks the continuity of stress, but also recharge and rejuvenates the cells. But one of the problem with the continuity of stress, that it deprives us from the deep sleep. Which leads to the accumulation of stress day by day and ultimately to the burn out

Early death to the cell becomes the main cause of various degenerative disorders and early death of the organism.

Yogic perspective

Yoga practices looks to increase the life span of cell via maintaining the youthfulness of the cells. There are five principles of yoga looking to restore the balance and health of cellular system.

  • Relaxation – normal breathing rate/heart rate in rhythmic manner
  • Rhythm – Para-sympathetic tone
  • Repair – healing
  • Rejuvenation – feel good
  • Reprogramming – transformation of personality

Skeletal system

Humans are born with more then 270 bones, some of them get fused with each other in the process of progressing towards the adulthood, and an adult has 206 bones.

Major functions of Skeleton are to shape, support, movement, protection, blood formation and mineral storage e.g. calcium, phosphorus etc.

Division of skeleton

  • Axial skeleton

The axial skeleton (80 bones) is consists of vertebral column (26), the rib cage (12 pairs of ribs and 1 sternum), and the skull (22 bones and 7 associated bones). The upright posture of humans is maintained by the axial skeleton, which transmits the weight of the head, trunk, and the upper extremities down to the lower extremities at the hip joints.

  • Appendicular skeleton

The appendicular skeleton (126 bones) is consists of shoulder/pectoral girdles (4), the upper extremities (60), the pelvic girdle (2), and the lower extremities (60).


The bones are all very much alive, growing and changing all the time like other parts of body. They are a combination of organic and inorganic compounds. The organic compound made up of cells and the osteoid (protein fiber called collagen). The osteoid makes up 1/3 of the matrix; it works to maintain hone’s structure, flexibility and tensile strength. The inorganic compound consists of minerals, largely calcium phosphate, which accounts for the hardness of the bones.

Different layers of bone

  • The outer most layer of bone is called periosteum. It’s a thin, dense membrane that contains nerves and blood vessels for the nourishment of the bone.
  • The next layer inward is made up of compact hone. This part is very strong for its weight bearing capacity.
  • Inside the compact bone are several layers of spongy hone. It is not as strong as compact bone, but still helps in overall strength of bone.
  • The spongy hone holds the innermost part, the bone marrow. Bone marrow is sort of like a thick jelly, two types of bone marrow red and yellow. Red bone marrow is production site of the blood and yellow is reserve of the fat.

Classification of bones

Bones can be classified by their shape and size. 121They come in different sizes and shapes, with each unique structure fulfilling a particular function or need. The shapes are long, short, flat, and irregular.

  • Long bones

Humerus, Ulna, Radius, Femur, Tibia, Fibula etc.

  • Short bones

Carpals, Tarsals etc.

  • irregular bones

Skull, Pelvis, vertebra etc.

Common disorder

  • Osteoporosis

Osteoporosis is a degenerative disorder of hones that leads to an increased risk of fracture. In osteoporosis, the bone mineral density (BMD) is reduced, bone microarchitecture deteriorates, and the amount and variety of proteins in bone are altered.

Common Causes

  • Dietary deficiency
  • Sedentary life style
  • Hormonal imbalances
  • Prolonged emotional stress
  • Prolonged medication

Yogic perspective

Osteoporosis can be prevented and treated through regular Yoga asanas, Pranayama with proper diet and lifestyle habits. Yoga asanas help to strengthen your bones and muscles slowly and gradually, preventing the onset of this condition and providing relief from the pain. Yoga asana with Pranayama helps in creating a balanced harmony between the ovaries, adrenals, para-thyroids, pituitary and pineal gland, and other glandular secretions thus


ensuring that the body receives a steady supply of the right hormones for maintaining bone strength and maximum health and well being.


An articulation, or joint, is a place where two bones come together. in terms of the amount of movement they allow, there are three types of joints: immovable, slightly movable and freely movable.

  • Fibrous joint (immovable)

In these joints, the bones come very close to each other at the point of contact and are separated only by a thin layer of connective tissue. The sutures in the skull are examples of immovable joints.

  • Cartilaginous joint (slightly movable)

In this type of joint, the bones are connected by fibrocartilage. The pubic symphasis is a slightly movable joint in which there is a fibrocartilage pad between the two bones. The joints between the vertebrae are also of this type.

  • Synovial joint (freely movable)

Most of the joints in the adult body are synovial, or freely movable joints. In this type of joint, the ends of the opposing bones are covered and protected with hyaline cartilage/articular cartilage, and they are separated by a space called the synovial cavity. The components of the joints are enclosed in a dense fibrous joint capsule. The outer layer of the capsule consists of the ligaments that hold the joint together. The inner layer is the synovial membrane that has a job to secrete synovial fluid into the cavity for its lubrication.

Types of synovial joint

There are different types of synovial joints when it conies to range of motion available. Some are relatively less mobile, but are more stable. Others have multiple degrees of movements on different plane and axis, but at the expense of greater risk and susceptibility to injury.

Major types with their possible movement

  • Hinge joint – flexion and extension
  • Pivot joint – rotation
  • Saddle joint – flexion, extension, abduction, adduction and circumduction
  • Condyloid joint – flexion, extension, abduction, adduction and circumduction
  • Ball and socket joint – flexion, extension, abduction, adduction, rotation and circumduction

Common disorders


Arthritis is a common medical condition that causes pain and inflammation within a joint.

The condition affects people of all ages including children. There are many different types of arthritis that cause a wide range of symptoms. Two of the most common are osteoarthritis and rheumatoid arthritis.

  • Osteoarthritis

Osteoarthritis is the most common form of arthritis. In people affected by this type of arthritis, the articular cartilage (connective tissue) between their bones gradually wastes away, leading to painful rubbing of bone on bone in the joints. The most frequently affected joints with this are in the hands, spine, knees and hips.

Osteoarthritis often develops in people who are over 50 years of age. However, it can develop at any age as a result of an injury or another joint-related condition.

  • Rheumatoid arthritis

Rheumatoid arthritis is a more severe, but less common, form of arthritis than osteoarthritis. It occurs when the body’s own defense mechanism/immune system attacks and destroys the affected joints, causing pain and swelling to occur. This can lead to a reduction in movement and the breakdown of bone and cartilage.

  • Gouty arthritis

Gout is caused by too much urea and uric acid in the blood. When uric acid levels in the blood are too

high, the uric acid may form hard crystals in the joints and due to this its painful to move the joint. Chances of getting gout are much higher in those people are overweight, drinking too much alcohol, or eat too much meat and fish.

Symptoms of arthritis

There are many different symptoms of arthritis and the symptoms you experience will vary depending on the type of arthritis you have. However, common arthritic symptoms include:

  • Joint pain, swelling, tenderness and stiffness
  • Inflammation in and around the joints
  • Restricted range of motion
  • Warmth and redness of the skin over the affected joint

Common Causes

  • Dietary imbalances
  • Sedentary life style
  • Postural imbalances/muscle tone
  • Hormonal imbalances
  • Prolonged emotional stress
  • Prolonged medication
  • Traumatic conditions

Yogic perspective

Yoga asanas help to overcome poor posture, which contributes to joint misalignment and the erosion of joint cartilage. Stretching tight muscles and strengthening weak ones encourage joints into a healthier functional relationship.

Yoga helps in the management and reduction of pain itself through the use of calming breathing practices, deep relaxation and meditation. As the body and the mind relax pain very often begins to diminish, as tension and stress is a contributory factor in the experience of pain.

Range of motion

All physical activities are made possible or helped by various movements and motions happening at different joints of the body. Each and specific joint has a range of motion depends on their structural and functional qualities in different direction, which is expressed in degrees. The device used to calculate the degree of movement is goninmeter.

Every movement of the joint is defined tinder three planes and axis Planes and axis of Movement

  • Sagittal Plane and frontal axis

Sagittal plane passes from front to rear dividing the body into two symmetrical halves right and left. Frontal axis is perpendicular to the sagittal plane.

  • Frontal Plane and sagittal axis

it passes from side to side and divides the body into two halves anterior and posterior. Sagittal axis is perpendicular to the frontal plane.

  • Transverse Plane and vertical axis

It passes from front to rear and divides the body into superior and inferior halves. Vertical axis is perpendicular to the transverse plane.

Types of Movement

There is more to the movement than just planes and axes. There are several “types” of movement that are further broken down into the following categories:

  • Flexion and extension
  • Adduction and abduction
  • Rotation (external/internal)
  • Circumduction

Joints and movements

  • Spinal column

Flexion, extension, lateral flexion and rotation

  • Shoulder girdle

Elevation, depression, retraction, protraction, upward/downward rotation and anterior/posterior tilt

  • Shoulder joint

Flexion, extension, abduction, adduction, external/internal rotation and circumduction

  • Elbow joint

Flexion, extension, supination and pronation

  • Wrist joint

Flexion, extension, ulnar and radial deviation

  • Pelvic girdle

Anterior/posterior/lateral tilt

  • Hip joint

Flexion, extension, abduction, adduction, external/internal rotation and circumduction

  • Knee joint

Flexion, extension and external/internal rotation (only when the knee is flexed)

  • Ankle joint

Planter flexion, dorsal flexion, inversion and eversion

Muscular system

The muscular system is composed of specialized cells called muscle fibers. Their predominant function is contractibility. Muscles, attached to bones or internal organs and blood vessels, are responsible for movement. Nearly all movement in the body is the result of muscle contraction.

The integrated action of joints, bones, and skeletal muscles produces obvious movements such as walking and running. Skeletal muscles also produce more subtle movements that result in various facial expressions, eye movements, and respiration.

In addition to movement, muscle contraction also fulfills some other important functions in the body, such as posture, joint stability, and heat production. The skeletal muscles are continually making fine adjustments that hold the body in stationary positions. Heat production, to maintain body temperature, is an important by-product of muscle metabolism. Nearly 85 percent of the heat produced in the body is the result of muscle contraction.


Tendons are the cords and straps made up of connective tissue that connect muscles to bones. The fibers of the tendon are embedded in the bone. This anchors the tendon strongly and spreads the force of the contraction, so the tendon won’t tear away easily.

Types of muscles

  • Skeletal muscle
  • Smooth muscle
  • Cardiac muscle

Types of muscle contraction

  • Isotonic and isometric

Isotonic Contractions

isotonic contractions are those which cause the muscle to change length as it contracts and causes movement of a body part There are two types of Isotonic contraction:

  • Concentric Concentric contractions are those, which cause the muscle to shorten as it contracts.
  • Eccentric Eccentric contractions are the opposite of concentric and occur when the muscle lengthens as it contracts.

Isometric Contractions

Isometric contractions occur when there is no change in the length of the contracting muscle.

Muscles working in a pair

Muscles usually work in pairs or groups, e.g. the biceps flexes the elbow and the triceps extends it. When muscles cause a limb to move through the joint’s range of motion, they usually act in the following cooperating groups:

  • Agonists

These muscles cause the movement to occur. They create the normal range of movement in a joint by contracting. Agonists are also referred to as prime movers since they are the muscles that are primarily responsible for generating the movement.

  • Antagonists

These muscles act in opposition to the movement generated by the agonists and are responsible for returning a limb to its initial position.

  • Synergists

These muscles perform, or assist in performing, the same set of joint motion as the agonists. Synergists are sometimes referred to as neutralizers because they help cancel out, or neutralize, extra motion from the agonists to make sure that the force generated works within the desired plane of motion.

  • Fixators

These muscles provide the necessary support to assist in holding the rest of the body in place, while the movement occurs. Fixators are also sometimes called stabilizers.

Major joints, muscles and movements

Neck movements
Flexion Extension Lateral flexion Rotation
SCM Erector spine SCM SCM
Trunk movements
Flexion Extension Lateral flexion Rotation
Rectus Abdomens Erector spine External/internal oblique Ext./internal oblique
Shoulder girdle movements
Elevation Depression Retraction Protraction
Trapezius Rhomboids Trapezius Pectorals minor
Upward rotation Downward rotation
Serratus anterior Rhomboids


Shoulder joint movements

Flexion                                                         Extension                                                 Abduction                                             Adduction

Deltoid anterior                                     Deltoid posterior                Deltoid all fibers                                  latisimus dorsi

External rotation                    internal rotation

Infra spinatus                    supra spinatus

Elbow joint movements

Flexion                                    Extension

Biceps                                     Triceps

Hip joint movements

Flexion                                   Extension                              Abduction                                                                         Adduction

Ilia psoas                                                    Gluteus maximus                 Gluteus medius-minimus                      Adductor brevis-longus

External rotation                   Internal rotation

Gluteus medius                      Gluteus minimus

Knee joint movements

Flexion                                    Extension

Biceps femoris                           Vastus Lateralis/Intermedius/Medialis

Ankle joint movements

Planter flexion                       Dorsal flexion

Gastrocnemius                        Tibialis anterior


Posture is the position in which you hold your body upright against gravity while standing, sitting or lying down. Good posture involves your body to stand, walk, sit and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities. Proper posture:

  • Keeps bones and joints in the correct alignment so that muscles are being used properly.
  • Helps decrease the abnormal wearing of joint surfaces that could result in arthritis.
  • Decreases the stress on the ligaments holding the joints of the spine together.
  • Prevents the spine from becoming fixed in abnormal positions.
  • Prevents fatigue because muscles are being used more efficiently, allowing the body to use less energy.
  • Prevents strain or overuse problems.
  • Prevents backache and muscular pain.
  • Contributes to a good appearance.

Postural imbalances

Postural imbalance refers to poor posture, which is an uneven distribution of body mass. If any part of the body is out of alignment, muscles adapt by shortening or lengthening. This can lead to muscle imbalance, which may leads to pain and injury.

Most common imbalances

  • Anterior pelvic tilt – lordosis-kyphosis
  • Posterior pelvic tilt – flat back
  • Lateral pelvic tilt – scoliosis


Asana, in the context of Yoga is “to be in a position that is firm, but relaxed and comfortable” for extended period of time.

  • Improves the alignment of the body against gravity
  • Leeds to Improved breathing
  • Leeds to Improved digestion and circulation
  • Leeds to Improved balance endocrinal secretion
  • Results as emotional balance
  • Improves nerve supply
  • Calms the nervous system
  • Leeds to the clarity of thoughts

Digestive system

After absorption, nutrients are used to synthesize body constituents. They provide the raw materials for the manufacture of new cells, hormones, enzymes and the energy needed for these and other processes and also for the disposal of waste materials

Digestive tract

  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum and anal canal

Accessory organs

3 pairs of salivary glands Pancreas


Gall bladder

Digestion of elementary substances Carbohydrate into glucose

Protein into amino acid

Lipid into fatty acid

Water, minerals, vitamins does not digestion

Yogic perspective

  • Proper diet
  • Proper quantity
  • Proper timings
  • Peaceful mind at the time of meals
  • Fasting to restore the rhythm of digestion

Respiratory system

The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system’s means of getting oxygen to the blood and ultimately to the cell.

Respiratory structure

  • Nose
  • Larynx – Voice box
  • Trachea – Windpipe
  • Bronchi
  • Lungs – Bronchial tree and Alveoli
  • Respiratory muscles – Diaphragm and intercostal


Air enters the respiratory system through the nose, and then passes through the larynx (where speech sounds are produced) and the trachea, which is a tube that enters the chest cavity. In the chest cavity, the trachea splits into two smaller tubes called the bronchi. Each bronchus then divides again forming the bronchial tubes. The bronchial tubes lead directly into the lungs where they divide into many smaller tubes, which connect to tiny sacs called alveoli.

 The average adult’s lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. Meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.

The diaphragm’s job is to help pump the carbon dioxide out of the lungs and pull the oxygen into the lungs. The diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. As the diaphragm contract and relaxes, breathing takes place. When the diaphragm contracts, oxygen is pulled into the lungs. When the diaphragm relaxes, carbon dioxide is pumped out of the lungs.

Breathing facts

  • Normal breathing rate – 12 breath/min.
  • Tidal volume – 500 ml
  • Residual volume – 2500 ml
  • Total volume – 6000 ml
  • Minute ventilation – 6000 ml/min.

Irregular breathing

  • Mouth breathing
  • Chest breathing
  • Rapid breathing
  • Arrhythmic pattern
  • Hyperventilation

Yogic perspective

Breath is the key when it comes to the all-physiological and psychological balances, just by observing the breath we can be aware of how the psycho-physiological activities influences the breath and vice versa, regulation of breath brings the regulation of body and mind. According to the Yogic point of view breathing needs to be strictly nasal, diaphragmatic, slow and rhythmic, Pranayama practices are made to eradicate all the breathing irregularities and establish better breathing pattern.

Circulatory system

The circulatory system is that permits blood and lymph circulation to transport nutrients (such as glucose, amino acids, fatty acid and electrolytes etc.), oxygen, carbon dioxide, hormones, blood cells, etc. to and from cells in the body to nourish it and help to fight diseases, stabilize body temperature and pH, and to maintain homeostasis.

This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which returns excess filtered blood plasma from the interstitial fluid (between cells) as lymph.


Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal. Blood is mostly liquid, with numerous cells and proteins suspended in it, making blood “thicker” than pure water. The average person has about 5 liters (more than a gallon) of blood.

A liquid called plasma makes up about hall of the content of blood. Plasma contains proteins that help blood to clot, transport substances through the blood, and perform other functions. Blood plasma also contains glucose and other dissolved nutrients.

About half of blood volume is composed of blood cells:IMI

  • Red blood cells, which carry oxygen to the tissuesE
  • White blood cells, which fight infections171
  • Platelets, smaller cells that help blood to clot



The human heart is an organ that provides a continuous blood circulation throughout the body by cardiac cycle and is one of the most vital organs in the human body. The heart is divided into four main chambers: the two upper chambers are called the left and right atrium and two lower chambers are called the right and left ventricles. There is a thick wall of muscle separating the right side and the left side of the heart called the septum.

  • Flow of the blood through the heart

Blood returns to the heart from the body via two large blood vessels, called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen is used.

The blood first enters the right atrium. It then flows through the tricuspid valve into the right ventricle. When the heart beats, the ventricle pushes the blood through the pulmonic valve into the pulmonic artery. This artery is unique: It is the only artery in the human body that carries oxygen-poor blood.

The pulmonic artery carries blood to the lungs where it “picks up” oxygen, and leaves the lungs and returns to the heart through the pulmonic vein. The blood enters the left atrium, and then descends through the mitral valve into the left ventricle. The left ventricle then pumps blood through the aortic valve, and into the aorta, the blood vessel that leads to the rest of the body.

  • Cardiac cycle

The cardiac cycle is the sequence of events that occurs when the heart beats. There are two phases of the cardiac cycle. In the diastole phase, the heart ventricles are relaxed and the heart fills with blood. In the systole phase, the ventricles contract and pump blood to the arteries. One cardiac cycle is completed when the heart fills with blood and the blood is pumped out of the heart.

Blood vessels

Blood vessels are intricate networks of hollow tubes that transport blood throughout the entire body. Blood delivers nutrients to and removes wastes from our cells.

Types of blood vessels

  • ArteriesE Arteries are elastic vessels that transport blood away from the heart. tA
  • Veins@ Veins are elastic vessels that transport blood to the heart. el
  • CapillariesM

Capillaries are extremely small vessels located within the tissues of the body that transport blood from the arteries to the veins.

Blood pressure

Blood pressure is the force of blood created against the walls of arteries. Blood pressure is recorded as two numbers—the systolic pressure (as the heart beats) over the diastolic pressure (as the heart relaxes between beats). The measurement is written one above or before the other, with the systolic number on top and the diastolic number on the bottom. For example, a blood pressure measurement of 120/80 mmHg (millimeters of mercury) is expressed verbally as “120 over 80.”

Cholesterol and circulatory system

Cholesterol is a soft, fat-like, waxy substance found in the bloodstream and in all the body cells. It is an important part of a healthy body because it’s used for producing cell membranes and some hormones, and serves other bodily functions. But a high level of cholesterol in the blood is a major risk factor for heart diseases.

The involuntary function of the body, like circulation, is controlled by the autonomic nervous system and the endocrine system. The autonomic nervous system is divided into two parts: the sympathetic and parasympathetic.

When the sympathetic nervous system is stimulated, a person’s stress level increases. Stress increases our heart rate, Again, when this system is stimulated beyond a point, it results in decrease in HDL level, rise in oxidized LDL level, and increase in vascular spasm. These changes in the body cause atherosclerosis, plaque formation, and increase in platelet stickiness.

Prolonged stress causes psychosomatic diseases like hypertension, metabolic syndrome etc.

The parasympathetic nervous system works against the sympathetic system, to balance the stress level. Practice of Yoga stimulates the parasympathetic system and combats stress.

Care should be taken to avoid negative emotions that dominate the mind [emotions like anger, hostility, resentment, jealousy, fear, vanity, egoism and criticism). These negative emotions induce secretion of hormones that increase the irritability of the myocardium (the muscle of the heart). Negative emotions also bring down the immunity level of a person, causing an overall deterioration of health.

In addition, mental relaxation through meditation contributes immensely in offsetting arteriosclerosis (coronary artery blocked due to the deposition of fats on the inner walls of the heart). Thus, owing to its many positive effects- direct and indirect on the cardiovascular system, yoga assumes a pivotal role in heart care.

Lymphatic system

The lymph system is a network of organs, lymph nodes, lymph ducts, and lymph vessels that make and move lymph from tissues to the bloodstream. The lymph system is a major part of the body’s immune system.

The Lymphatic system includes the tonsils, spleen, and thymus.

  • Lymph

Lymph is the fluid that circulates throughout the lymphatic system. The lymph is formed when the interstitial fluid (extra-cellular fluid) is collected through lymph capillaries.

As the blood and the surrounding cells continually add and remove substances from the interstitial fluid, its composition continually changes. It is then transported through lymph vessels to lymph nodes before emptying ultimately into the right or the Left subclavian vein, where it mixes back with blood.

Lymph returns excess interstitial fluid to the circulation. Lymph may pick up bacteria and bring them to lymph nodes where they are destroyed. Lymph also transports fats from the digestive system.

  • Lymphatic vessels

Lymphatic vessels are thin walled, valve structures that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessels are devoted to propulsion of the lymph from the lymph capillaries, which are mainly concerned with absorption of interstitial fluid from the tissues.

Generally, lymph flows away from the tissues to lymph nodes and eventually to either the right lymphatic duct or the largest lymph vessel in the body, the thoracic duct. These vessels drain into the right and left subclavian veins respectively.

  • Lymph nodes

Lymph nodes are soft, small, round- or bean-shaped structures. They usually cannot be seen or easily felt. They are located in clusters in various parts of the body, such as the neck, armpit, groin, and inside the center of the chest and abdomen.

Lymph nodes make immune cells that help the body fight infection. They also filter the lymph fluid and remove foreign material such as bacteria and cancer cells. When bacteria are recognized in the lymph fluid, the lymph nodes make more infection-fighting white blood cells, which causes the nodes to swell. The swollen nodes are sometimes felt in the neck, under the arms, and groin.

  • Spleen

Spleen is an organ above stomach and under ribs on the left side. It is about as big as fist. The spleen is part of lymphatic system, which fights infection and keeps body fluids in balance. It contains white blood cells that fight infection. Spleen also helps control the amount of blood in body, and destroys old and damaged blood cells.

  • Thymus

Thymus is the part of lymphatic system made up of lymphatic tissues, as a gland produces a hormone called thymosin, which works as an instruction for the bone marrow to produces white blood cells, after the production these specific cells comes to the thymus for their growth and maturation, once they are ready goes to the different parts of the body to strengthen the immune system.

Urinary system

The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.

The urinary system keep chemicals, such as potassium and sodium, and water in balance and remove a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys, where it is removed.


Two kidneys – a pair of organs located below the ribs toward the middle of the back. Their function is to remove liquid waste from the blood in the form of urine; keep a stable balance of salts and other substances in the blood; and produce erythropoietin, a hormone that aids the formation of red blood cells. One of the important functions of the kidneys include blood pressure regulation.

  • Nephron

The kidneys remove urea from the blood through tiny filtering units called nephrons, Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules or the kidney.


Two ureters – narrow tubes that carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

Urinary bladder

Bladder – a triangle-shaped, hollow organ located in the lower abdomen. The bladder’s walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up totwo cups of urine for two to five hours.


Urethra – the tube that allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

Nervous system

The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.

The nervous system consists of the Central nervous system and Peripheral nervous system.

Central nervous system

The central nervous system is divided into two major parts: the brain and the spinal cord.

  • The brain The brain lies within the skull and is shaped like a mushroom. The brain consists of four principal parts:
  •  Cerebrum

The cerebrum forms the bulk of the brain and is supported on the brain stem. The cerebrum is divided into two hemispheres. Each hemisphere controls the activities of the side of the body opposite that hemisphere.

The hemispheres are further divided into four lobes:

  • Frontal lobe
  • Temporal lobes
  • Parietal lobe
  • Occipital lobe

Limbic system

The Limbic System is the area of the brain that regulates emotion and memory. It directly connects the lower and higher brain functions. It influences emotions, the visceral responses to those emotions, motivation, mood, and sensations of pain and pleasure. The Limbic System is comprised of the following parts.

  • Thalamus

Thalamus means “inner room” in Greek, as it sits deep in the brain at the top of the brainstem. It is called the gateway to the cerebral cortex, as nearly all sensory inputs pass through it to the higher Levels of the brain.

  • Hypothalamus

The hypothalamus sits under the thalamus at the top of the brainstem. Although the hypothalamus is small, it controls many critical bodily functions: Controls autonomic nervous system Center for emotional response and behavior, Regulates body temperature, Regulates food intake, Regulates water balance and thirst, Controls sleep-wake cycles, Controls endocrine system.

  • Amygdala

The Amygdala is important for making associations across stimulus modalities (a certain fragrance often elicits an associated visual image). It appears to be responsible for the influence of emotional states on sensory inputs. This produces a spectrum of sensory perceptions from apparently identical stimuli (ex. the sound of one’s own motorcycle is never perceived as noise). Thought to be responsible for face recognition.

  • Hippocampus

The Hippocampus is very important in the transition of information from short to long­term memory, Since the Hippocampus is also part of the Temporal Lobe; damage to that portion of the brain can result in a loss of memory.

Brain stem

The brainstem is the region 01 the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, medulla oblongata, and the pons. Motor and sensory neurons travel through the brainstem allowing For the relay of signals between the brain and the spinal cord. The brainstem coordinates motor control signals sent from the brain to the body. The brainstem also controls life supporting autonomic functions of the peripheral nervous system.

The brainstem controls several important functions of the body including:

  • Alertness
  • Arousal
  • Breathing
  • Blood Pressure
  • Digestion
  • Heart Rate
  • Other Autonomic Functions


In Latin, the word cerebellum means little brain. The cerebellum is the area, which controls motor movement coordination, balance, equilibrium and muscle tone.

  • Spinal cord

The spinal cord is one of the two major components of the central nervous system, like the brain, it is completely encased in bone. It resides within the vertebral column, connects directly to the medulla section of the brain, receives sensory messages and sends them to the brain, sends motor messages from the brain, also acts independently from the brain: e.g., reflexes

Peripheral nervous system

Peripheral nervous system is the extension of Central nervous system to reach to each and every corner of the body. Functionally it is divided into two divisions somatic and autonomic.

  • Somatic nervous system Somatic section is voluntary in its nature and regulates the functioning of skeletal muscles.
  • Autonomic nervous system

Autonomic section is involuntary in its nature and regulates the functioning of smooth and cardiac muscles. Autonomic section is further divided into two as Sympathetic and Para-sympathetic.

o    Sympathetic – fight or flight

o    Para-sympathetic – rest and digest

Neuron – nerve cell

A neuron or nerve cell is an electrically excitable cell that processes and transmits information through electrical and chemical signals. A chemical signal occurs via a synapse, a specialized connection with other cells. Neurons connect to each other to form neural networks. Neurons are the core components of the nervous system, which includes the brain, spinal cord, and peripheral.

A number of specialized types of neurons exist:

  • Sensory neurons

They respond to touch, sound, light and numerous other stimuli affecting cells of the sensory organs that then send signals to the spinal cord and brain.

  • Motor neurons They receive signals from the brain and spinal cord, cause muscle contractions, and affect glands.
  • I nterneurons They connect neurons to other neurons with in the same region of the brain or spinal cord.

Endocrine system

The nervous system coordinates rapid and precise responses to stimuli using action potentials. The endocrine system maintains homeostasis and long-term control using chemical signals. The endocrine system works in parallel with the nervous system to control growth and maturation along with homeostasis. Endocrine systems works through glands, they secrete their products, hormones, directly into the blood. The main endocrine glands include the pituitary gland, pineal gland, thyroid, para-thyroid, pancreas, ovaries, testes, and adrenal glands. passed through the blood to arrive at a target organ, which has cells possessing the appropriate receptor. The roles of hormones in selecting target cells and delivering the hormonal message.

  • Pituitary gland

The pituitary gland is often referred to as the “master gland” of the body, since it regulates many activities of other endocrine glands. Located above the pituitary gland is the hypothalamus. The hypothalamus

connects nervous system with endocrine system and decides which hormones the pituitary should release by sending iteither hormonal or electrical messages.

In response to hormonal messages from the hypothalamus, the pituitary gland releases the following hormones:

o     GH (growth hormone) – increases size of muscle and bone

o     TSH (thyroid stimulating hormone) – stimulates the thyroid gland to release T3 and T4 to stimulate metabolism in other cells throughout the body

o     FSH (follicle stimulating hormone) – stimulates ovarian follicle production in women; stimulates sperm production in men

o     LH (luteinizing hormone) – stimulates ovaries to produce estrogen in women; stimulates sperm production in men

o     Prolactin – stimulates breast tissue in nursing mothers to produce milk

o     ACTH (adrenocorticotropic hormone) – causes the adrenal glands to produce important substances that have properties similar to steroids

In response to electrical messages from the hypothalamus, the pituitary gland releases the following hormones:

  • Arni (antidiuretic hormone) – stimulates the kidneys to reabsorb fluid and produce less


o     Oxytocin – initiates labor, uterine contractions and milk ejection in mothers

  • Pineal gland Pineal gland is the source of melatonin, a hormone that regulates circadian rhythm (sleep cycle).
  • Thyroid gland.

The thyroid makes three hormones that it secretes into the bloodstream. Two of these hormones, called thyroxine (T4) and triioduthyronine (r3), increase your body’s metabolic rate. Essentially, the body’s metabolic rate is how qiiicky the cells in your body use the energy stored within them. Thyroid hormones make cells use more energy. Ely controlling how much energy our cells use, thyroid hormones also help to regulate our body temperature. Heat is released when energy is used, increasing our body temperature. Thyroid hormones also play a role in making proteins, the building blocks of the body’s cells. They also increase the use of the body’s fat and glucose stores.

The other hormone that the thyroid makes is called calcitonin. This helps to control the levels of calcium and phosphorus in the blood. These minerals are needed, among other things, to keep bones strong and healthy.

  • Para-thyroid gland

The parathyroid glands release a hormone called parathyroid hormone. This hormone helps to control the levels of three minerals in the body: calcium, phosphorus and magnesium. Parathyroid hormone has a number of effects in the body:

o it causes the release of calcium from bones.

o     It causes calcium to be absorbed (taken up into the blood) from the intestine.

o     It stops the kidneys from excreting (getting rid of) calcium in the urine.

  • Pancreas

The pancreas is a gland behind your stomach and in front of your spine. It produces juices that help break down food and hormones including insulin and glucagon, which help in control blood sugar levels.

  • Adrenal glands

The adrenal glands (also known as suprarenal glands) sit at the top of the kidneys. They are chiefly responsible for releasing hormones in response to stress through the synthesis of corticosteroicis such as cortisol, adrenaline and noradrenaline.

  • Ovaries

Ovaries secrete both estrogen and progesterone. Estrogen is responsible for the appearance of secondary sex characteristics for females at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone prepares uterus for pregnancy, and mammary gland for lactation. Progesterone functions with estrogen by promoting menstrual cycle.

  • Testes

The primary functions of the testes are to produce sperm (spermatogenesis) and to produce androgens, primarily testosterone.

Homeostasis and stress

Stress and homeostasis are at odds with one another within the body of a living organism. An organism is designed to be in a state of homeostasis, where all the systems within its body are functioning optimally. Stress pushes the organism out of homeostasis, forcing it to compensate for changes in the environment or within its internal systems. In biology, stress may refer to physical and environmental challenges as well as emotional and psychological ones that can have an effect on an organism’s body.

Organisms are never fully free from stress and are thus never in a true state of homeostasis, though they are usually in a state that is relatively stable. Stresses in the environment, such as those caused by temperature or the presence of danger, as well as those within the organism, such as those caused by hunger, thirst, or emotional discomfort will all cause the organism to move out of homeostasis as the stressor is dealt with. Most of the time, stress and homeostasis are in a balance that allows the organism to survive though not always to thrive.

Essence of Yogic perspective

All the aspects of human organism, functioning at their best to experience the culmination of the potential, called self-realization. Few points to consider

Proper diet

Proper Digestion -> process of digestion depends on two things

  • Peristalsis (rhythmic contraction of digestive tract)
  • and secretion (enzymes to break down food), these two things are under the regulation of Autonomic nervous system
  • Regulation of Autonomic nervous system is possible with breathing
  • Proper Posture is a prerequisite for proper breathing

Proper circulation -> Proper nourishment and Proper elimination of waste materials

  • Proper nourishment needs proper diet and proper digestion as a pre-requisite
  • Proper digestion depends upon autonomic nervous system
  • Elimination of waste is also depends of autonomic nervous system
  • Autonomic nervous system we can regulate through out breathing
  • Posture needs to be proper for the breathing

Balanced metabolism -> proper use of energy resources

  • Metabolism is a balance of expenditure and savings of energy resources
  • Autonomic nervous system is the regulator
  • Proper diet, breathing and posture becomes very important

Emotional maturity -> endocrinal/hormonal balance

Autonomic nervous system regulates the hormonal secretion

  • Breathing and posture are still important
  • But perception becomes more important
  • Previous experience and memories plays their roles
  • Thoughts are the building block of perception

Spiritual life style

  • Complementary living
  • Existence is co-existence

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