Animal Organization and Homeostasis

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Animal Organization and Homeostasis
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Tissues

• Specialized cells of the same type that perform a
  common function in the body
• Types
• Epithelial
• Connective
• Muscular
• Nervous

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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)

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Glandular epithelial

• Secretes a product
• Exocrine
• into a duct
• Endocrine
• into the blood stream

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Connective tissue

• Most abundant
• Each type has
• specialized cells
• Ground substance
• Protein fibers
• Types
• Fibrous connective
• (loose and dense)
• Adipose
• Cartilage
• Bone
• blood

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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

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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

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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

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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
• RBCs small, no nucleus, round
• WBC larger, have a nucleus, phagocytes, produce
  antibodies
• Platelets involved in blood clotting
• Lymph in lymph vessels, absorbs excess fluid

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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

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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

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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

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Skin

• Largest organ
• Functions for protection and thermoregulation
• Contains receptors that monitor touch, pressure,
  temperature
• and pain
• Epidermis
• Dermis
• subcutaneous

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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

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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

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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)

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Organ systems

• 2 main body cavities
• Dorsal (cranial and vertebral cavity)
• Ventral (thoracic, abdominal and pelvic cavity)

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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