Animal structure and function

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Animal structure and function

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Tissues

• Epithelial
• Connective
• Muscle
• Nervous

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Epithelial tissue

• Epithelial tissue (epithelium)
• Covers all surfaces of the body
• Epidermis (ectoderm)
• Outer portion of skin
• Endoderm
• Lining of inner surfaces of digestive tract
• Mesoderm
• Inner surface of body cavities

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Epithelial tissue

• Closely packed
• Tight junctions
• One/or few cell layers thick
• Selective absorption in the intestines
• Rapid gas exchange in lungs
• Protection from microbes, water loss

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Epithelial tissue

• Regenerative capabilities
• Liver (gland from epithelial tissues)
• Epidermis every 2 weeks
• Stomach lining every 2-3 days

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Epithelial tissue

• Types
• Based on cell thickness
• Shape on exposed surface
• Simple
• One layer thick
• Stratified
• Multiple layers of cells

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Epithelial tissue

• Shapes of cells
• Cuboidal
• As wide as they are tall (like dice)
• Columnar
• Taller than wide (like bricks on end)
• Squamous
• Flat like floor tiles

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Epithelial tissues
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Epithelial tissue

• Simple squamous
• Lining of lungs, capillary walls and blood
  vessels
• Simple cuboidal
• Lining of some glands
• Simple columnar
• Lining of stomach, intestines and parts of
  respiratory tract

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Epithelial tissue

• Stratified squamous
• Outer layer of skin and mouth
• Keratin
• Water resistant protein

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Epithelial tissue

• Exocrine glands (duct system)
• Duct
• Connection from gland to tissue
• Secrete/absorb chemical solutions
• Sweat and sebaceous glands
• Lining of intestines lungs that secrete mucous

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Epithelial tissue

• Endocrine glands (ductless glands)
• Hormones
• Secreted into blood stream

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Glands
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Connective tissue

• Holds tissues organs together
• Derived from mesoderm
• Loosely packed cells
• Scattered in an extracellular matrix

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Connective tissue

• Matrix
• Composed of a web of fibers
• In a foundation of liquid, jellylike or solid
• Fibers (proteins) are collagen, elastic, or
  reticular

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Connective tissue

• Collagen
• Non-elastic-doesnt tear easily
• Elastic
• Makes tissue elastic
• Elastin (protein)
• Reticular
• Thin, branched, joins connective tissue to
  adjacent tissues

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Connective tissue

• Cells in matrix
• Fibroblasts
• Produce secrete extracellular matrix
• Macrophages
• Engulf foreign bodies debris
• Mast cells heparin

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Connective tissue types

• 1. Loose connective tissue
• Beneath skin between organs
• Support, insulation, food storage
• Adipose tissue (fat)
• Cells become larger when gain weight
• Shrink with weight loss

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Connective tissue

• 2. Dense connective tissue
• Tendons, ligaments, sheath around organs
  (periosteum), dermis of skin
• Support, strong connections
• 3. Special connective tissue
• Cartilage, bone, blood,

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Connective tissue
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Special connective tissue

• Cartilage
• Consists of chondroitin (glycoprotein) collagen
• Strong, flexible tissue, absorb stress
• Joints, ear pinna, nose, intervertebral discs,
  larynx
• Chondrocytes
• Cartilage cells

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Cartilage
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Bone

• Embryos---more cartilage
• Cartilage is replaced with bone cells or
  osteocytes
• Matrix hardens with crystals of calcium phosphate
  mixed with collagen

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Bone

• Osteoblasts
• Lay down new bone
• Osteoclasts
• Dissolve bone
• Osteons
• Unit of bone structure
• Contains calcified matrix, osteocytes, nerve
  fibers, blood vessels

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Bone

• Flat bones
• Long bones
• Spongy bone
• Contains marrow
• Blood cells formed
• Compact bone
• More dense, gives strength

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Bone
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Bone
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Blood

• Plasma (matrix)
• Cells
• RBC (erythrocytes)
• Contain hemoglobin (carries oxygen)
• WBC (leukocytes)
• Neutrophils, eosinophils, basophils, lymphocytes,
  monocytes
• Platelets (thrombocytes)

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Blood
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Blood

• Plasma contains
• Wastes, nourishment
• Hormones
• Na, Ca2, other ions
• Fibrinogen, albumin, antibodies

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Muscle tissue

• Movement
• Organization of actin myosin filaments
• Smooth, skeletal cardiac muscles
• Striated muscles skeletal cardiac
• Skeletal muscles voluntary control
• Smooth cardiac muscles involuntary control

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Muscle tissue

• Smooth muscle
• Walls of blood vessels, stomach, intestines
• Viscera
• Internal organs
• Made of sheets of cells each with a single nucleus

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Muscle tissue

• Skeletal muscle
• Attached by tendons to bones
• Contract move bones

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Muscle tissue
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Muscle tissue

• Cardiac muscle
• Small interconnected cells
• Linked by gap junctions
• Openings allow small substances electrical
  charges to pass between cells
• Myocardium
• Single functioning units

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Nerve tissue

• Neurons
• Cell body, dendrites, axon
• Neuroglia
• Supporting cells
• Insulate neurons
• Eliminate foreign bodies

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Nerve tissue

• Dentrites
• Thin, branched extensions
• Receive impulses
• Axons
• Single extension of cell body
• Carries impulse away
• Myelin sheaths, insulating cover

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Neurons
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Neurons

• Sensory neurons
• Eye,ears, surface of skin
• Motor neurons
• Brain spinal cord
• Interneurons
• Brain spinal cord
• Neurons within the CNS

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Neurons
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Summary

• Epithelial tissues
• Simple or stratified
• Cuboidal, columnar, squamous
• Connective tissues
• Loosely packed, tightly packed
• Special (bone, cartilage, blood)
• Matrix

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Summary

• Muscle tissues
• Smooth, cardiac, skeletal
• Nerve tissues
• Neurons (cell body, dentrites, axons)
• Sensory, motor and interneurons

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Coordination

• Hormones
• Nervous system
• Homeostasis

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Homeostasis

• Dynamic constancy of internal environment
• Dynamic because conditions fluctuate
• Narrow range
• pH
• Temp
• Glucose
• Oxygen

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Regulation

• 1. Negative feedback loops
• 2. Positive feedback loops

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Negative feedback

• media\40_08NegativeFeedback_A.html

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Positive feedback
media\40_08PositiveFeedback_A.html
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Negative feedback loops

• Sensors
• Measure internal environment
• Integrating center
• Receives information from sensors
• Compares to normal range
• Responds

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Negative feedback loops

• Effectors
• Muscles or glands
• Receive information from center
• Response

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Negative feedback loops

• Temperature increase
• Hypothalamus senses deviation
• Sends signals to relieve heat
• Sweating vasodilation
• Reach baseline
• Negative feedback stops response

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Negative feedback loops

• Temperature decrease
• Hypothalamus sends signals
• Shiver, vasoconstriction
• Temp to baseline
• Negative feedback stops response

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Thermoregulation
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Fig. 40-9
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
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Negative feedback loops

• Glucose (eat a meal)
• Elevated blood level
• Islets of Langerhans (sensor, center)
• Insulin
• Lowers blood sugar (uptake in muscle, fat liver
  cells)
• Negative feedback stops insulin release

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Positive feedback loops

• Uterine contractions
• Pressure from baby on uterus
• Causes contractions
• Causes more stretching
• More contractions
• Continues until birth

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Positive feedback loop

• Blood clotting
• Clotting factors stimulate the formation of more
  factors
• Clot forms
• Maintain blood volume

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Bioenergetics

• Overall flow transformation of energy in an
  animal
• Determines nutritional needs
• Animal size, activity and environment

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Fig. 40-17
Organic molecules in food
External environment
Animal body
Digestion and absorption
Heat
Energy lost in feces
Nutrient molecules in body cells
Energy lost in nitrogenous waste
Carbon skeletons
Cellular respiration
Heat
ATP
Biosynthesis
Cellular work
Heat
Heat
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Metabolic rate

• Amount of energy an animal uses in a unit of time
• Torpor
• Physiological state of low activity with low
  metabolism
• Hibernation
• Long term torpor