Protection Support

And Locomotion

INTEGUMENTARY SYSTEM

(skin)

The skin is the largest organ of the body, and together with its appendages(hair, nails, and cutaneous glands) it makes up the integumentary system.

The skin consist of two principal layers. The EPIDERMIS is composed of stratified

squamous epithelium divisible into four to five layers; stratum corneum, stratum lacidum, stratum glanulosum, stratum spinosum, and stratum basale.

The deepest portion of epidermis is made up of rapidly dividing cells, as these cell are pushed farther away from the dermis by the new cells that are forming , they received less nourishment and die. Before dying , they produce large amount of tough, waterproofing protein which is called keratin

Structure of the skin

The DERMIS lies below the epidermis, it is made up of elastic connective tissues.

The dermis is a thick layer that support the skin and binds it to the muscles and bone lying underneath it.

Within the dermis are blood vessels, lymph vessels, nerves, sense receptors, sebaceous glands, sweat glands and hair follicles.

The two portions of dermis are the upper papillary layer and the deeper reticular layer.

Beneath the dermis is a layer of fats or adipose tissues.

The sebaceous glands produce oily secretion that provide a protective coating to the skin and hair, and keep them soft and pliable.

Sweat glands are made of tiny –coiled tubes that open to the surface of the skin through holes called pores

The skin keeps microorganisms and other foreign materials from entering to the body,

It also keeps the body from drying out. The skin excretes a small amount of urea and salts

in sweat which is 99 percent water. Skins major roles in excretion is the removal of

excess heat. Skin also helps keep heat in when the body is too

cool. The blood vessels in the skin is narrow slightly ,

reducing the supply of blood to the skin capillaries.

The body also sweats less , in this manner less heat is lost from the body, if the body is cold it can produce heat by muscle tension and shivering .

Functions of the skin

The skeletal system

The skeletal system of an adult human has 206 named bones, each bone is an organ that takes a part in the totality of the skeletal system. Bone is a type of connective tissue that is hard and inflexible, and serve a number of purpose.

* they serve as sites of attachment for skeletal muscles, and they serve as levers that make body parts moves when these muscles contract.

* they give the body its general shape and support body system.

* they serve as storage places for minerals, such as calcium and phosphorus.

* they serve as places where red blood cells and some white blood cells are produced.

Bone is made up of living bone cells, connective tissue fibers, and inorganic compounds. It is an active tissue.

A basic part of the structure is the collagen, a protein material with great strenght, when bones are being formed living cells known as osteoblast, secrete collagen and certain polysaccharides.

The collagen forms fibers that are bound together by polysaccharides, which act as cement.

Bone is formed when phosphate and calcium ions from the body fluid combine forming calcium phosphate.

The calcium phosphate precipitates as crystal within the mass of collagen fibers and cement the hardness and heaviness of the bone are due to calcium phosphate.

The osteoblast trapped in small cavities inside the bone substance called osteocytes

The Osteocytes arranged in decreasing circles with a common center called Haversian Canals which contain blood vessels and nerves.

The blood vessels carry oxygen and nutrients to the bone cells and remove water.

Cartilage, like bone, is a type of connective tissue. In the embryo most of the skeleton is cartilage.

Ossification , minerals are laid down , and much of the cartilage slowly changes to bones.

Types of Bones Shapes of Bones Examples

Long bones Longer than they are wideAnd function as lever.

Femur, tibia, fibula, metatarsals, phalanges, humerus, radius, ulna and metacarpals.

Short bones Somewhat cube-shaped and nearly equal in length and width.

Carpal and tarsal bones

Flat bones Generally thin and have a broad dense surface.

Cranium, sternum, ribs and scapula.

Irregular bones Complex and varied shaped

Vertebrae, and certain facial bones

Short bones

Long bones

IRREGULAR BONES

Flat bones

HUMAN SKELETON

Human skeleton – the adult human skeleton consist of 206 bones.

- has two main parts a) Axial skeleton b) Appendicular skeleton

Parts of Axial Skeleton1) SKULL a) Cranium – upper part of the

skull, - houses and

protects the brain. b) facial and jaw bones – the

remaining bones of the

skull

2) HYOID - a single bone that acts as support for the tongue.

3) AUDITORY OSSICLES4) VERTEBRAL COLUMN - known as backbone, - has 26 bones called vertebrae. - has discs of cartilage that separate the

vertebrate from each other. These discs acts as shock absorbers and allows the spine to bend.

5) THORAX- known as the rib cage, - made up of sternum, coastal cartilages ,ribs and

the bodies of the thoracic vertebrae. - the ribs are fastened at the back of upper

vertebrae and at the front of the sternum or breast bone.

6) CHEST CAVITY- the space enclosed by the sternum, ribs and backbone.

- heart and lungs are protected by the ribs and sternum

1) PECTORAL GIRDLES a) scapula – shoulder blades b) clavicle – collarbones 2) UPPER EXTREMITIES a) humerus – arm bone b) radius and ulna – bones of forearms c) carpals – wrist bones d) metacarpals – palm bones e) phalanges – finger bones3) PELVIC GIRDLE a) two hip bones- provide a story and stable

support for vertebral column.4) LOWER EXTREMITIES a) femur - thigh bone b) tibia and fibula - skin bone c) tarsals - ankle bones d) metatarsals - bones of foot e) phalanges - bones of fingertoes .

Parts of Appendicular Skeleton

Human skeleton

.

JOINTS - a point in the skeleton where bones

meet. - there are two types of joints: a) Inmovable Joints b) Movable Joints

- bones are tightly fitted together, - cranium

2) MOVABLE JOINTS ( ACCORDING TO MOVEMENTS)

a) hinge joints – permit only back and forth motion. - elbow knee b) ball and socket joints - allows movement in all directions -the ball shaped end of one bone is into the cup-like hollow or socket of another bone. c) pivot joints- side by side and up and down movements . - base of the skull

1) INMOVABLE JOINTS

d) gliding joints – bending and twisting

- wrist, joints between vertebrae

LIGAMENTS – a synovial fluid that serves as lubricant and reduces the friction in joints .

- tough fibrous bands of connective tissues of the movable joints.

MUSCULAR SYSTEM

The most obvious difference between plants and animals is that plants remain in one spot throughout their life while most animals move about from one place to another – swimming, flying or walking.

Movement is a major characteristic of animals/humans.

All animals use the same basic mechanism; muscle contraction, and a far greater than what the gravity is exerting .

The human body has three different kinds of muscles; skeletal, cardiac. And smooth.

Skeletal Muscles

CARDIAC MUSCLES

SMOOTH MUSCLES

Types of Muscles

Location Structure Function

Skeletal Muscles

Attached primarily to bones

Striated muscles with long cylindrical , multinucleate

voluntary muscles

Cardiac Muscles

Walls of the heart

Striated muscle with branching, generally uninucleate cells that interdigitate at specialized junctions,(intercalated disc)

Involuntary muscles

Smooth Muscles Mostly in the walls of hollow internal organs.

Nonstriated muscles with spindle shaped cells with central nuclei; cells arranged closely to form sheets.

Involuntary muscles

Structural And Functional Characteristics Of Muscles

SKELETAL MUSCLES skeletal or striated muscles are used in

locomotion and all other voluntary movements. Skeletal muscle tissues are not made of

clearly defined , separated cells. A skeletal muscle is made up of bundles of

muscles fibers bound together by connective tissue.

Under a light microscope , the muscle fibers appears stripes or striated. They show alternating bands of lights and dark striations.

Myofibril –bundle of small fibers, made up of still finer protein filaments one thick and one thin/

The thick filaments are myosin, the thin ones are actin.

SKELETAL MUSCLES

VOLUNTARY MUSCLES

All voluntary movement is started and coordinated by impulses from the brain and spinal cord.

Voluntary movements include any action that is under the conscious control. It requires the actions of skeletal muscles or striated muscles.

Skeletal muscles are fastened to the bones by strong fibers of connective tissue called TENDONS. Muscles can pull when they are relaxed.

They must always work in antagonistic pairs. The two muscles in an antagonistic pairs move a bone in opposite direction.

Bending and extending of the arms at the elbow shows how muscles and the bones work together to initiate movements.

When the biceps on the front of the upper arm contract, the arm bends, because the muscles the biceps muscles bends or flexes at the joint it is called the FLEXOR.

The triceps muscles in the back of the arms relaxes making it possible for the arm to bend . When the triceps muscles contracts, the biceps muscles relaxes, and the arm extended or straightened.

When the triceps muscles extends at the joint it is called EXTENSOR .

As long as you are conscious, your skeletal muscles are never completely relaxed. Instead , your brain keeps all your muscles partly contracted. This is called MUSCLE TONE. It keeps the muscles ready for the powerful contractions or movements.

SMOOTH MUSCLES In addition to the skeletal muscles, which

under voluntary control. The body also contains muscles that work involuntary, or without conscious control.

these involuntary muscles tissues are called SMOOTH MUSCLES or UNSTRIATED MUSCLES.

It is found in the walls of digestive organs, in the arteries and veins, in the diaphragm and in other internal organs. The cells of smooth muscles are long overlap to form sheets of muscles rather than bundles of fibers.

CARDIAC MUSCLES Cardiac muscles are only found in the heart,

like skeletal muscles, cardiac muscles are striated. But cardiac muscles cells are branching uninucleate cells that fit together at tight junctions called; INTERCALATED DISC.

These part permit the cardiac muscles to move as a unit.

Cardiac muscles is under involuntary action to pump blood throughout the body.