Animal Organization and Homeostasis

Tissues Specialized cells of the same type that

perform a common function in the body Types

Epithelial Connective Muscular Nervous

Epithelial tissue Covers surfaces and lines body cavities Mostly functions in protection Exposed to environment on 1 side, basement

membrane on the other that anchors it to the connective tissue

Named according to shape of cell Squamous (flat), cuboidal (cube) and columnar (column) Stratified (layered), pseudosratified (looks layered)

Glandular epithelial Secretes a product

Exocrine into a duct

Endocrine into the blood stream

Connective tissue Most abundant Each type has

specialized cells Ground substance Protein fibers

Types Fibrous connective

(loose and dense) Adipose Cartilage Bone blood

Fibrous connective tissue Contain fibroblast cells within a gel matrix Loose fibrous – support Adipose – energy reservoir, insulation Dense fibrous – found in tendons and

ligaments, contains collagen fibers

Supportive connective tissue Cartilage – cells in chambers called lacunae

surrounded by a gel like matrix 3 types of cartilage (based on fibers in matrix)

Hyaline – most common, fine collagen fibers Elastic - more flexible Fibrocartilage – strong collagen fibers

Bone Hard matrix of inorganic salts around protein

fibers Compact bone – shaft of long bones

Cylindrical structures called osteons Bone cells found within lacunae

Spongy bone – end of long bones Contains bony bars and plates with space between Built for strength

Fluid Connective Tissues Blood – formed elements and plasma

Hematopoiesis – production of blood cells, in red bone marrow

Transports nutrients and oxygen to tissue fluid, distribute heat and fluid, ion and pH balance

RBC’s – small, no nucleus, round WBC – larger, have a nucleus, phagocytes, produce

antibodies Platelets – involved in blood clotting Lymph – in lymph vessels, absorbs excess fluid

Muscular tissue Made of cells called muscle fibers

Actin – thin, myosin – thick Movement and generation of heat

3 types Skeletal – voluntary, striated Smooth – visceral, involuntary, no striations Cardiac – muscles of the heart, involuntary,

striated, intercalated disks

Nervous tissue Contain neurons (1 trillion on average)

3 parts: axon, cell body, dendrite Functions in sensory input, integration of data,

and motor output Neuroglia – support and nourish neurons

Microglia - phagocyte Astroglia – provide nutrients Oligodendroglia – form myelin in brain

Organs and organ systems Organ – 2 or more types of tissues working

together to perform the same function Organ system – organs working together to

carry out a process

Skin Largest organ Functions for protection and thermoregulation Contains receptors that monitor touch,

pressure, temperature and pain

Epidermis Dermis subcutaneous

Epidermis Stratified squamous Hair follicles, sebaceous glands, sweat glands Skin cells are pushed to surface of skin and

slough off Melanocytes – cells that produce melanin,

pigment, UV rays induce production (vit.D) Basal cell carcinoma and malignant

melanoma are types of skin cancer

Dermis and Subcutaneous Contains collagen and elastic fibers Overstretching due to fast weight gain can

cause stretch marks Blood vessels and sensory receptors

Subcutaneous – not true part of skin, source of energy, produces padding, overall rounded appearance

Accessory organs of the skin Nails – protective covering, can be useful

medically hair – begin in dermis, extend out of

epidermis, dead, hardened epidermal cells Each follicle has an oil gland that when clogged,

produces white heads or black heads (oxidized sebum)

Glands – sweat (sudoriferous)

Organ systems 2 main body cavities:

Dorsal (cranial and vertebral cavity) Ventral (thoracic, abdominal and pelvic cavity)

Homeostasis Maintaining and internal balance Negative feedback – keeps a variable close to

a particular value ex. – body temp. Positive feedback – brings a greater change in

the same direction ex. Oxytocin and birth