The document describes the structure and function of the human heart. It states that the heart is a four-chambered organ divided into right and left sides by a septum. The right atrium receives blood from the venae cavae and pumps it to the lungs, while the left atrium receives blood from the lungs and pumps it into the systemic circulation. Electrical signals cause the heart muscle to contract in a regular rhythm. Valves ensure blood flows in only one direction with each heartbeat.

1. Human Body
Body Parts
Bone & Muscles

2. Human Body

3. Human heart
Organ that pumps blood, circulating it to all
parts of the body
The human heart is a four-chambered
double pump with its right and left sides
fully separated by a septum and
subdivided on both sides into an atrium
above and a ventricle below. The right
atrium receives venous blood from the
superior and inferior venae cavae (see
vena cava) and propels it into the
pulmonary circulation. The left atrium takes
in blood from the pulmonary veins and
sends it into the systemic circulation.
Electrical signals from a natural pacemaker
cause the heart muscle to contract. Valves
in the heart keep blood flowing in one
direction. Their snapping shut after each
contraction causes the sounds heard as
the heartbeat. See also cardiovascular
system.

4. Structure of
human heart
Structure of the human heart.
Oxygen-rich blood from the lungs
enters the heart through the
pulmonary veins, passing into the
left atrium and on to the left
ventricle. Contraction of the
muscles of the left ventricle forces
blood into the aorta. The mitral
valve prevents blood from moving
back into the left atrium during
contraction. Various arteries branch
off from the aorta to supply blood to
all parts of the body. Oxygen-poor
blood draining from the body into
the superior vena cava and inferior
vena cava flows to the right atrium,
through the tricuspid valve, and into
the right ventricle. As the right
ventricle contracts, oxygen-poor
blood passes through the
pulmonary valve into the pulmonary
arteries and on to the lungs to
receive oxygen.

5. circulation
Process by which nutrients, respiratory gases, and metabolic products
are transported throughout the body.
In humans, blood remains within a closed cardiovascular system
composed of the heart, blood vessels, and blood. Arteries carry
blood away from the heart under high pressure exerted by the
heart's pumping action. Arteries divide into smaller arterioles, which
branch into a network of tiny capillaries with thin walls across which
gases and nutrients diffuse. Capillaries rejoin into larger venules,
which unite to form veins, which carry blood back to the heart. (See
artery; capillary; vein.) The right and left heart chambers send blood
into separate pulmonary and systemic circulations. In the first, blood
is carried from the heart to the lungs, where it picks up oxygen and
releases carbon dioxide; in the second, blood is carried between the
heart and the rest of the body, where it carries oxygen, nutrients,
metabolic products, and wastes.

6. circulation
Human circulatory system. Oxygen-rich
blood is shown in red, oxygen-poor blood
in blue. The pulmonary circulation consists
of the right ventricle and the exiting
pulmonary artery and its branches, the
arterioles, capillaries, and venules of the
lung, and the pulmonary vein. Unlike the
other arteries and veins, the pulmonary
arteries carry deoxygenated blood and the
pulmonary veins carry oxygenated blood.
The aorta arises from the left ventricle. The
brachiocephalic artery arises from the
aorta and divides into the right common
carotid and right subclavian arteries. The
left and right common carotids extend on
either side of the neck and supply much of
the head and neck. The left subclavian
artery (arising from the aorta) and the right
subclavian artery supply the arms. In the
lower abdomen, the aorta divides into the
common iliac arteries, which give rise to
external and internal branches supplying
the legs.

7. Lungs
Either of two light, spongy, elastic organs in the chest, used
for breathing.
Each is enclosed in a membrane (pleura). Contraction of
the diaphragm and the muscles between the ribs draw
air into the lungs through the trachea, which splits into
two primary bronchi, one per lung. Each bronchus
branches into secondary bronchi (one per lobe of lung),
tertiary bronchi (one per segment of lung), and many
bronchioles leading to the pulmonary alveoli. There
oxygen in the inspired gas is exchanged for carbon
dioxide from the blood in the surrounding capillaries.
Adequate tissue oxygen supply depends on sufficient
distribution of air (ventilation) and blood (perfusion) in the
lungs. Lung injuries or diseases (e.g., emphysema,
embolism, pneumonia) can affect either or both.

8. respiratory system
In humans, the diaphragm and, to a lesser extent,
the muscles between the ribs generate a
pumping action, moving air in and out of the
lungs through a system of pipes (conducting
airways), divided into upper and lower airway
systems. The upper airway system comprises
the nasal cavity (see nose), sinuses, and
pharynx; the lower airway system consists of the
larynx, trachea, bronchi, bronchioles, and
alveolar ducts (see pulmonary alveolus). The
blood and cardiovascular system can be
considered elements of a working respiratory
system. See also thoracic cavity.

9. As air enters the nasal cavity through the nostrils, it is warmed and moistened by mucous
membranes of the nasal turbinates before entering the pharynx. Stiff hairs lining the vestibule inside
the nostrils help filter the entering air. The air-filled sinuses adjacent to the nasal cavity produce
mucus. The larynx connects the pharynx with the trachea or windpipe. The cartilaginous epiglottis
prevents food from entering the larynx during swallowing. A left and right primary bronchus supply
each lung with air from the trachea. They divide into smaller secondary and tertiary bronchi; the
smallest divisions, bronchioles, lead to the cup-shaped, thin-walled alveoli, which occur in clusters
(alveolar sacs). Oxygen and carbon dioxide are exchanged between the alveoli and surrounding
capillaries. Oblique fissures or grooves of each lung separate the upper lobe from the lower lobe.
The horizontal, or transverse, fissure of the right lung forms a middle lobe. Movement of the
diaphragm along with the ribs and rib muscles causes expansion and contraction of the lungs
during breathing.

10. digestion
Process of dissolving and chemically converting food for absorption by cells.
In the mouth, food is chewed, mixed with saliva, which begins to break down
starches, and kneaded by the tongue into a ball for swallowing. Peristalsis
propels it through the esophagus and the rest of the alimentary canal. In the
stomach, food mixes with acid and enzymes, which further break it down.
The mixture, called chyme, enters the duodenum, the first part of the small
intestine. Bile from the liver breaks up fat globules. Enzymes from the
pancreas and intestinal glands act on specific molecules, breaking
carbohydrates down into simple sugars, proteins into amino acids, and fats
into glycerol and fatty acids. These products are absorbed by the
bloodstream. Indigestible substances, such as fibre, pass into the large
intestine, where water and ions are reabsorbed and feces held for excretion.

11. Digestive
system
Major organs of the human digestive system. Food
taken in by the mouth is guided by the tongue as it is
sheared and ground by the teeth. The bolus of
chewed food is moistened and lubricated with saliva
secreted by the salivary glands. Enzymes in the
saliva begin the breakdown of starches. The epiglottis,
a flap of tissue, prevents food from the pharynx from
entering the larynx during swallowing. Muscles in the
esophagus wall contract in waves to move the food to
the stomach. Gastric juices secreted by the stomach
contain a mixture of substances (including enzymes
and hydrochloric acid) that break down the food into a
semiliquid mass called chyme. The chyme passes
into the small intestine, where food molecules are
broken down into sugars, amino acids, and fatty acids.
These useful substances are absorbed into the
bloodstream as the food passes through the
duodenum, jejunum, and ileum. The pancreas
secretes digestive enzymes into the duodenum. The
liver secretes bile salts that make insoluble fats
entering the small intestine water-soluble and
vulnerable to enzymatic action. Excess bile salts are
stored in the gallbladder. The large intestine (colon)
serves to remove water and electrolytes from the
digested chyme and to compact and store
undigestible material, called feces. Fecal matter is
moved by muscular contractions into the rectum and
expelled from the anus.

12. larynx
Voice Box
Hollow, tubular structure connecting the pharynx with the
trachea, through which air passes on the way to the
lungs.
The larynx consists of a framework of cartilage plates, with
a ridge in front (Adam's apple); the epiglottis, a flaplike
projection up into the throat that covers the airway during
swallowing to keep food and liquid from entering; and the
vocal cords, whose vibration produces the sound of the
voice

13. Larynx
Structure
(A) Frontal view and (B) cutaway
side view of the human larynx. The
larynx is composed of cartilage
plates that are joined together by
muscles and ligaments. The thyroid
cartilage, the largest, forms a
prominence in front called the
Adam's apple. The leaf-shaped
epiglottis, attached to the upper part
of the thyroid cartilage, closes
during swallowing. The vocal cords
in the cavity of the larynx are large
folds in the mucous membrane
lining the larynx. They stretch
between the thyroid cartilage in
front and the arytenoids cartilages
in the back. As air passes between
them, they vibrate to emit sound.

14. kidney
One of a pair of organs that maintain water balance and expel
metabolic wastes.
Human kidneys are bean-shaped organs about 4 in. (10 cm) long, in
the small of the back. They filter the entire 5-quart (about 4.5-liter)
water content of the blood every 45 minutes. Glucose, minerals, and
needed water are returned to the blood by reabsorption. The
remaining fluid and wastes pass into collecting ducts, flowing to the
ureter and bladder as urine. Each kidney has over 1 million
functional units (nephrons) involved in the process of filtration and
reabsorption. The kidneys also secrete renin, an enzyme involved in
blood pressure regulation. Disorders include kidney failure, kidney
stones, and nephritis

15. Kidney
Structure
Cross section of a kidney. The kidney is
made up of an outermost cortex, a middle
medulla, and an inner pelvis. Blood enters
via the renal artery, which branches into
smaller vessels, each of which terminates
in a tuft of capillaries (glomerulus). Fluids
from the blood are forced out of the
glomerulus into the surrounding Bowman's
capsule during filtration. The glomerulus,
Bowman's capsule, and associated renal
tubule make up the nephron. Any important
substances filtered from the blood
(including glucose, minerals, and much of
the water) are returned to it by reabsorption
in the renal tubule. The medulla is divided
into conical masses of tissue (renal
pyramids) that contain the collecting ducts
for the fluid (urine) not reabsorbed into the
blood. Water is further removed from the
urine as it passes through the collecting
ducts into the funnel-shaped renal pelvis,
which leads to the ureter.

16. urinary system
System that produces and discharges urine to rid the body of
waste products.
It consists of the kidneys, which balance electrolytes in blood,
retaining and adding needed ones and removing unneeded or
dangerous ones for excretion; the ureters, two thin muscular
tubes 10–12 in. (25–30 cm) long that move the urine by
peristalsis; the hollow, muscular bladder, which receives and
stores it; and the urethra, through which it leaves the body. In
women the urethra is 1.5 in. (4 cm) long. In men it is longer
(since it passes through the penis), about 8 in. (20 cm), and
carries semen from the prostate gland as well as urine.
Urinary disorders, which can lead to dehydration or edema
and to a dangerous buildup of waste and toxic substances,
include kidney failure, tumours, and bladder and kidney
stones.

17. endocrine system
Group of ductless glands that secrete hormones necessary for normal
growth and development, reproduction, and homeostasis.
The major endocrine glands are the hypothalamus, pituitary, pineal,
thyroid, parathyroids, adrenals, islets of Langerhans in the pancreas,
ovaries, and testes. Secretion is regulated either by regulators in a
gland that detect high or low levels of a chemical and inhibit or
stimulate secretion or by a complex mechanism involving the
hypothalamus and the pituitary. Tumours that produce hormones
can throw off this balance. Diseases of the endocrine system result
from over- or underproduction of a hormone or an abnormal
response to a hormone.

18. endocrine system, human: major
glands of the human endocrine
system
Major glands of the human endocrine system.
The hypothalamus stimulates the pituitary
gland and influences food intake, weight
regulation, fluid intake and balance, thirst,
body heat, and the sleep cycle. Pituitary
hormones stimulate growth, egg and sperm
development, milk secretion, and release of
hormones by other glands. The pineal gland
may play a significant role in sexual maturation
and the circadian rhythm. Thyroid hormones
regulate the metabolic rate of tissues,
stimulate the contraction of heart muscle, and
are necessary for normal growth and brain
development before birth and during infancy.
Parathyroid hormone regulates calcium,
phosphorus, and magnesium levels. The
adrenal glands regulate salt and water
retention, some reactions of the immune
system, and blood pressure. The islets of
Langerhans regulate blood sugar levels. The
ovaries and testes produce hormones that
regulate the reproductive system and that
produce male and female secondary sex
characteristics.

19. Bones of Human
Body

20. The Brain
Concentration of nerve tissue in the front or upper end
of a body.
It handles sensory information, controls motion, is vital
to instinctive acts, and in higher vertebrates is the
centre of learning. Vertebrate brains consist of the
hindbrain (rhombencephalon), midbrain
(mesencephalon), and forebrain (prosencephalon).
The hindbrain comprises the medulla oblongata and
the pons, which connects the spinal cord with higher
brain levels and transfers information from the cerebral
cortex to the cerebellum. The midbrain, a major
sensory integration centre in other vertebrates, serves
primarily to link the hindbrain and forebrain in
mammals. Large nerve bundles connect the
cerebellum to the medulla, pons, and midbrain. In the
forebrain the two cerebral hemispheres are connected
by a thick bundle of nerve fibres (corpus callosum) and
are divided by two deep grooves into four lobes
(frontal, parietal, temporal, and occipital). The
cerebrum, the largest part of the human brain, is
involved with its more complex functions. Motor and
sensory nerve fibres from each hemisphere cross over
in the medulla to control the opposite side of the body.

21. Side view of the brain showing its major structures.
The large cerebrum is divided into two halves, or
hemispheres, connected by the corpus callosum,
a band of nerve fibres. Two grooves divide the
hemispheres into four lobes: frontal, temporal,
parietal, and occipital. Many nerve cells are found
in the convoluted cerebrum's outer surface, or
cerebral cortex, which controls sensory and motor
activities. The thalamus relays incoming sensory
impulses from the spinal cord to the cortex. The
hypothalamus's many functions include control of
breathing, blood flow, temperature regulation, and
emotions. The pituitary gland is attached to and
regulated by the hypothalamus. The midbrain
relays signals between the forebrain and hindbrain.
The cerebellum, along with the cerebrum, plays a
role in voluntary movement as well as balance.
The pons serves as a relay point linking the
medulla oblongata, midbrain, cerebellum, and
cerebrum. The medulla, lying between the pons
and the spinal cord and continuous with both,
plays a role in essential involuntary regulatory and
reflexive responses (including breathing,
swallowing, and heartbeat) and relays signals
between the spinal cord and other brain regions

22. Parts of Brain
1. Cerebrum :
Largest part of the brain.
The two cerebral hemispheres consist of an inner core of myelinated
nerve fibres, the white matter, and a heavily convoluted outer
cortex of gray matter (see cerebral cortex). Nerve fibres in the
white matter connect functional areas of the cortex in the same
hemispheres, connect functional areas of the cortex in opposite
hemispheres, and connect the cerebral cortex to lower centres
(e.g., the spinal cord). A front-to-back fissure divides the
cerebrum's two hemispheres. Each hemisphere controls the
opposite side of the body. The corpus callosum, a thick band of
white matter, connects them, allowing integration of sensory data
and responses from both sides of the body. Other important
cerebral structures include the hypothalamus and the thalamus.

23. 2. Cerebellum
Part of the brain that integrates sensory input from the
inner ear and from proprioceptors in muscle with nerve
impulses from the cerebrum (see cerebral cortex),
coordinating muscle responses to maintain balance and
produce smooth, coordinated movements.
Located below the cerebral hemispheres and behind the
upper medulla oblongata and pons, each of its two
connected hemispheres has a core of white matter within
a cortex of gray matter. Disorders usually produce
neuromuscular disturbances, in particular ataxia.

24. Eyes
Organ that receives light and visual images.
Non-image forming, or direction, eyes are found among worms, mollusks, cnidarians, echinoderms,
and other invertebrates; image-forming eyes are found in certain mollusks, most arthropods, and
nearly all vertebrates. Arthropods are unique in possessing a compound eye, which results in their
seeing a multiple image that is partially integrated in the brain. Lower vertebrates such as fish
have eyes on either side of the head, allowing a maximum view of the surroundings but producing
two separate fields of vision. In predatory birds and mammals, binocular vision became more
important. Evolutionary changes in the placement of the eyes permitted a larger overlap of the two
visual fields, resulting in the higher mammals in a parallel line of direct sight. The human eye is
roughly spherical. Light passes through its transparent front and stimulates receptor cells on the
retina (cones for colour vision, rods for black-and-white vision in faint light), which in turn send
impulses through the optic nerve to the brain. Vision disorders include near- and farsightedness
and astigmatism (correctable with eyeglasses or contact lenses), colour blindness, and night
blindness. Other eye disorders (including detached retina and glaucoma) can cause visual-field
defects or blindness

25. 1. Eyes-Structure
Structure of the human eye. The outer portion
consists of the white protective sclera and
transparent cornea, through which light enters.
The middle layer includes the blood-supplying
choroid and pigmented iris. Light passing into
the interior through the pupil is regulated by
muscles that control the pupil's size. The
retina comprises the third layer and contains
receptor cells (rods and cones) that transform
light waves into nervous impulses. The lens,
lying directly behind the iris, focuses light onto
the retina. The macula lutea, in the centre of
the retina, is a region of high visual acuity and
colour discrimination. Nerve fibres pass out
through the optic nerve to the brain's visual
centre. The eye's anterior and posterior
chambers contain a watery fluid that nourishes
the cornea and lens. The vitreous humour
helps maintain the eye's shape. A thin layer of
mucous membrane (conjunctiva) protects the
eye's exposed surface. External muscles,
including the medial rectus and lateral rectus
muscles, connect and move the eye in its
socket.

26. Tooth
Any of the hard structures in the mouth used for biting and chewing and in
speech.
Each consists of a crown above the gum and one or more roots below it,
embedded in the jaw. Its inner pulp contains the blood and nerve supply for
the bonelike dentin, covered in the crown by enamel, the hardest tissue in
the body. Twenty primary (baby) teeth come in by age 2 1/2 and fall out
between ages 5 and 13 to be replaced by 32 permanent teeth. The incisors,
in front, are shaped mostly for biting, the pointed canines for tearing, and
the premolars and molars for grinding food. The teeth are subject to caries
(decay), caused by acid from bacteria in plaque, a yellowish film that builds
up on teeth. Misalignment of teeth between the upper and lower jaws can
grind down the teeth and cause problems in chewing. Elsewhere, it is a
cosmetic problem. Both can be treated with braces

27. Structure Of Tooth
Cross section of an adult molar. The
crown (the part of the tooth above the
gum) is protected by a hard outer
layer of enamel. The roots sit in a
socket in the jawbone and are
covered with cementum, a bonelike
material. The periodontal ligament
anchors the cementum in the jaw and
cushions the tooth from the
pressures of chewing. The tooth's
main portion, the dentin, surrounds
the soft pulp, which carries the blood
vessels and nerves. Specialized cells
of the pulp project threadlike
extensions into the dentin through
narrow channels and serve to form
new dentin from minerals in the blood.

28. THANK YOU
Name : MUKUL
Class : X ‘B’
K.V.S sec-14 Gurgaon
Second shift