Why we look the way we do? (Human Body Systems)

Of all the living things, the human body in particular has been a source of curiosity by most of us.

Why we look the way we do? Why we do the things we do like walking, running, feeling, seeing, hearing and a lot more intrigue us

The human body is a machine that does many things. To do these things, it needs many parts. All these parts together are what we are.

Integumentary System

The largest organ of the integumentary system which is made up of multiple layers of epithelial tissues that guard the underlying muscles and organs of the body. It plays the most important role in protecting the body against pathogens. Its other main functions are insulation, regulation of body temperature, sensation and the synthesis of Vitamins B and D. Skin is considered as one of the most important parts of the body.

Epidermismade up of stratified squamous layer of

epithelial tissue10 to 30 cells thick, about as thick as this

page.Dermismade up of fibrous connective tissue

containing collagen and elastic fibers.also contains muscle fibers, glands,

pigment cells, blood vessels and sensory nerves.

15 to 40 times thicker than the epidermis.provides structural support for all the

epidermis and as matrix for any nerve endings, muscles and specialized cells in the skin.

Skeletal System

Functions:1. Support the body.2. Attachment of muscles.3. Protection of internal organs. 4. Act as levers for movement.5. Production of blood cells.6. Gives stability and shape to the body.

There are total of 206 bones in an adult human

distributed as follows:

skull ( cranium + face ) = 22 ( 8 + 14 )Ears = 6hyoid = 1vertebral column = 26sternum = 1ribs = 24pectoral girdle and forelimbs = 64pelvic girdle and hindlimbs = 62

Muscular System Muscles make up about half of the body’s bulk. Working with the skeleton, they generate the energy to move, make precise and intricate hand movements, lift objects, and even speak. Involuntary muscles, including the specialized cardiac muscle and all smooth muscles, provide the essential power for the respiratory, cardiovascular and digestive systems.

Digestive SystemFunctions:

1. Ingestion of food2. Breaking down of complex substance ( food ) into simple forms ( nutrients )3. Absorption of digested food4. Egestion of excretion of undigested food

Types of Digestion as to action:* Mechanical digestion – food is converted into small pieces by physical means such as mastication by the teeth.* Chemical digestion – food is converted into simpler forms by the action of enzyme/s.

Deglutition - complicated process that involves the coordinated activity of the tongue, soft palate, pharynx and esophagus

Metabolism

Metabolism - all of the physical and chemical activities in your body that convert or use energy. These include things like breathing, digesting food, and circulating blood.Catabolic reactions are reactions that involve the breakdown of biomolecules. Anabolic reactions - reverse of catabolic reactions. Build large biomolecules from smaller ones.

1. Refers to all chemical reactions necessary to maintain life.__________________.2. The process by which food is broken down into smaller particles or molecules for use in the human body.______________________.3. Muscular tube that provides a passageway for food and air.______________________.4. Straight, collapsible tube about 25 cm (10 inches long) and essentially a passageway that conducts food by peristalsis to the stomach ___________________.5. J-shaped, muscular, distensible sac, approximately 25 to 30 centimeters long.. _______________.6. Digestive juice in the stomach. Under normal conditions, two to three liters of it are produced everyday._________________.7. Stores waste food products and absorbs small amounts of water and minerals. ________________.8. Largest glandular organ of the body weighing from 3 to 4 pounds (1.4 to 1.8 kg) and is a soft, dark red or chocolate-colored mass._____________________.9. Body’s major digestive organ and is about 20 feet (6m) long and empties into the large intestine. It carries on most of the digestive process. _________________.10. Tiny fingerlike projections in the wall of the small intestine.____________________. 11. A gland lying crosswise in the abdomen just below the liver. It is a pinkish-yellow gland about 6-8 inches (15.20 cm) long, 1 ½ inches (3.8 cm) wide, and 1 inch (2.5 cm) thick which produces a digestive juice and the hormones insulin and glucagons.________________.

Respiratory SystemThe respiratory tract, working together with breathing muscles, carries air into and out of the lungs. The cardiovascular system transport these gases to and from all body tissues, supplying vital oxygen and removing waste carbon dioxide. A variety of viruses, bacteria, and chemicals contaminate most of the air we breath; overcoming these threats to our health is a vital role played by the immune system.

• Lung is the organ of external respiration (breathing) present in human beings. It is vital in maintaining life and acts as an exchange point where oxygen from the air is substituted for carbon dioxide in the blood. • Pleura is a continuous, thin, elastic membrane that covers the outside of the lungs and the inner walls of the chest cavity. • Alveoli are the 300 millions of air sacs emanating from the bronchioles making up the bulk of the lungs.

Breathing

Cardiovascular SystemCirculation - means by which food is carried to the tissues of the body and wastes are carried away.

1.Transport the oxygen and carbon dioxide, soluble food materials, organic wastes, and hormones

2. Regulation of the pH of tissue

3. Protection of the body against invading microbes

4. Regulation of body temperature in warm-blooded animals

The Blood A specialized

connective tissue The main transporting

medium of the body 8% of total body

weight (4 to 6 liters in average adult)

Considered to be the ‘essence of life’

Composition of blood:Plasma - fluid portion of the bloodFormed Elements:• Erythrocytes or red blood corpuscles (RBC) Small, biconcave disks with polysaccharides on the outer membrane• Leukocytes or white blood cells (WBC) less than 1% of the cells in human blood• Thrombocytes or blood platelets in humans. Involved in blood clotting or coagulation

ABO GROUPS

An antigen: any substance that causes your immune system to produce antibodies against it. may be a foreign substance from the environment, such as chemicals, bacteria, viruses, or pollen. may also be formed inside the body, as with bacterial toxins or tissue cells.

An antibody:a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include microorganisms (bacteria, fungi, parasites, and viruses) and chemicals.may be produced when the immune system mistakenly considers healthy tissue a harmful substance. This is called an autoimmune disorder. each type of antibody is unique and defends the body against one specific type of antigen.

The Heart

• main pumping organ of the body• highly muscular organ located in the mid-ventral region of the thoracic cavity• enclosed by a tough connective tissue, the pericardium• An adult’s heart is about 3 inches (13 cm.) long, 3 ½ inches (9 cm.) wide and 2 ½ inches (6.4 cm.) thick.• The septum divides the heart into right and left portions. • Valves control the flow of blood through the heart.

Each heart is a sequence of muscle contractions and relaxation called the cardiac cycle.

Blood Vessels

The Lymphatic System • Consists of transport tubes and lymphoid organs ( lymph vascular system,) which supplements pulmonary and the systematic circulation. • When the tissue fluid has moved into these tubes, it is called the lymph. • The lymphoid organs, which take part in defense responses, are structurally and functionally connected with both the blood and lymph vascular system.

Urinary System

The brain is the seat of both consciousness and creativity. Through the spinal cord and nerve branches, the brain also controls all body movement. The nervous system works with endocrine glands to monitor and maintain the other body systems

Neuron

The spinal cord, the sparkling white continuation of the brain stem is approximately 17 inches (42 cm ) long. Functions of the spinal cord1.Reflex activities/Reflex Action2.Conduction of sensory impulses - - upward through ascending tracts to the brain.3.Conduction of motor impulses - from the brain down through descending tracts to the efferent neurons that supply muscles or glands.

According to the direction of the nerve impulses, the functional classification groups of neurons travel relative to the Central Nervous System. Afferent or sensory neurons are the neurons carrying sensory input to the Central Nervous System. Efferent neurons are the neurons carrying motor output away from the Central Nervous System.

Efferent neurons are of two distinct systems. • Somatic Nervous System is the system of efferent nerves leading from the central nervous system to the skeletal muscles. • Autonomic Nervous System is composed of efferent nerves leading from the central nervous system to cardiac cells, muscle cells, smooth muscles cells and glands.

A neuron is separated from a next neuron by a junction or a tiny gap called a synapse. No matter how close neurons are they do not actually touch each other. Synaptic cleft is the space between two neurons and to cross them will require the actions of the neurotransmitters.

Autonomic Nervous System

Eyes

PARTS OF THE EYESclera or white of the eye is a firm membrane that forms the outer layer of the eyeball.Cornea is a transparent convex membrane found in front of the eye that refracts the light rays to focus on the retina.Lacrimal Glands are situated in recesses just above each eye. They secrete tears composed of water, salts and the bacteria-killing enzyme lysozome. Eyelids form a pair of protective shutters closing instantly if injury is feared. They also spread tears over the cornea keeping it moist and free from infection.Choroid that is rich in blood vessels lines the inner surface of the sclera.Melbonian glands are modified sebaceous glands associated with the eyelid edges producing an oily secretion that lubricates the eye.Iris is the part of the eye that regulates the amount of light that enters the eye lying behind the cornea and in front of the lens.Pupil a rounded opening in the iris through which light passes.Lens is a flexible biconvex crystal-like structure situated behind the pupil. It divides the eye into two chambers:a. Aqueous chamber a clear watery fluid, which helps maintain intraocular pressure or pressure inside the eye, and also provides nutrients for the lens and cornea.b. Vitreous chamber a gel - like substance, which prevents the eyeball from collapsing inward by reinforcing it internally.Retina is the light sensitive layer lining the eye. It contains nerve fibers and specialized cells called rods and cones, which are the photoreceptors. 1. The rods about 125 million are essential for seeing in dim light. They contain a pigment known as visual purple, which is broken down in the light and regenerated in the dark.2. The cones about 6-7 million, function in bright light and are necessary for sharp vision. They are most concentrated in the fovea, a small depression in the retina.Ocular muscles allow vision in different directions without turning the head and allow the eye be swiveled around in the socket.

Male Reproductive System

Female Reproductive System

Endocrine System