Transcript Animal Organization and Homeostasis

Animal Organization and
Homeostasis
Tissues
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Specialized cells of the same type that
perform a common function in the body
Types
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Epithelial
Connective
Muscular
Nervous
Epithelial tissue
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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
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Squamous (flat), cuboidal (cube) and columnar (column)
Stratified (layered), pseudosratified (looks layered)
Glandular epithelial
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Secretes a product
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Exocrine
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into a duct
Endocrine
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into the blood stream
Connective tissue
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Most abundant
Each type has
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specialized cells
Ground substance
Protein fibers
Types
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Fibrous connective
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(loose and dense)
Adipose
Cartilage
Bone
blood
Fibrous connective tissue
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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
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Cartilage – cells in chambers called lacunae
surrounded by a gel like matrix
3 types of cartilage (based on fibers in matrix)
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Hyaline – most common, fine collagen fibers
Elastic - more flexible
Fibrocartilage – strong collagen fibers
Bone
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Hard matrix of inorganic salts around protein
fibers
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Compact bone – shaft of long bones
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Cylindrical structures called osteons
Bone cells found within lacunae
Spongy bone – end of long bones
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Contains bony bars and plates with space between
Built for strength
Fluid Connective Tissues
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Blood – formed elements and plasma
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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
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Made of cells called muscle fibers
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Actin – thin, myosin – thick
Movement and generation of heat
3 types
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Skeletal – voluntary, striated
Smooth – visceral, involuntary, no striations
Cardiac – muscles of the heart, involuntary,
striated, intercalated disks
Nervous tissue
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Contain neurons (1 trillion on average)
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3 parts: axon, cell body, dendrite
Functions in sensory input, integration of data,
and motor output
Neuroglia – support and nourish neurons
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Microglia - phagocyte
Astroglia – provide nutrients
Oligodendroglia – form myelin in brain
Organs and organ systems
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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
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Largest organ
Functions for protection and thermoregulation
Contains receptors that monitor touch,
pressure, temperature
and pain
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Epidermis
Dermis
subcutaneous
Epidermis
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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
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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
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Nails – protective covering, can be useful
medically
hair – begin in dermis, extend out of
epidermis, dead, hardened epidermal cells
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Each follicle has an oil gland that when clogged,
produces white heads or black heads (oxidized
sebum)
Glands – sweat (sudoriferous)
Organ systems
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2 main body cavities:
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Dorsal (cranial and vertebral cavity)
Ventral (thoracic, abdominal and pelvic cavity)
Homeostasis
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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