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
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