Animal form and function

Common problems

All cells need aqueous environment

Gas exchange

Nourishment

Excrete waste

Move

Form and function

Anatomy = form

Physiology = function

Examples:Capillaries and alveoli: 1 cell thick, allow gas ex.Muscle cells: long fibers, allow long lever armRBC: smooth, round allow flow through vesselsSkin: many cells thick, allow for scrapes without lots

of blood loss

Body plans

Need: exchange with environment

Need: aqueous environment for each cell

Protist: 1 cell: exchange across cell membrane

Mammals

Simple diffusion?

Adaptations

Elephant: millions of cells must get glucose and oxygen.Aqueous solution for all cells = interstitial fluid

Increase surface area within organ system by:Folds and protrusions

Tissue

4 types of tissue

Muscle: contractile

Nervous: conduct impulses

Epithelial: lines things, secretion

Connective: holds things together

Muscle tissue

Muscle:

Most abundant tissue

Smooth, cardiac (desmosomes), skeletal

Proteins: actin and myosin

Second messenger: Ca++

ATP needed for contraction

Nervous tissue

Nervous

Excitable, conducts impulses

Neuron

CNS: brain and spinal cord PNS

Connective tissue

Connective tissue: cells in a matrix with proteins

Blood to bone Matrix: liquid to solid

Fibers: collagen, elastic, reticular

Epithelial tissue

Epithelial: linings, secretes

Tight junctions: no leaking, small intestine

Desmosomes: anchor: skin

Simple to stratified

Organs

No organs: sponges and cnidariansHave groups of different tissue types together for

more complex function.

Bioenergetics

Flow of energy through animal

Metabolic rate: amount of Energy per unit timeMeasure by heat lostOr oxygen consumed

Bioenergetic strategies

Endothermic: maintain body temperature:BirdsMammals

Exothermic: warmed by external sourceSome very stable If in a stable environment Invertebrates, fish

Differ in source of warmth

Metabolic rate

Amount Energy needed per gram of body weight inversely related to body sizeMouse has high metabolic rateElephant has low metabolic rate. BUT, requires more

energy overall

Metabolic rate

Smaller animals have higher metabolism: greater surface to volume ratio: harder to maintain body temperature.

BMR

Basal metabolic rate: at rest

Endotherm: 1,600 – 2,000Kcal/day

Maximum rate: can not sustain for long

Use: ATP that’s already presentThen make some anaerobically by glycolysisStart to break down glycogen in liver and muscle

cells

Homeostasis

Maintain stable internal environmentReceptor – control center- effector

Conformers: may let one variable change with environment.

Feedback loops

Positive feedback: childbirth

Negative feedback: 1 product of reaction goes back and shuts down earlier step in reaction

Homeostasis: thermoregulation

Body temperature monitored in hypothalamus receptor

Information integrated in CNS Integration center

Effector organs: If cold: skeletal muscle: shiver

Erector pili: hair stands up Smooth muscle: close capillary beds in periphery

If hot: sweat gland

Adaptations for thermoregulation

1. insulation: feathers, hair, fat

2. circulatory: vasodilate, vasoconstrict, concurrent heat exchange (birds, marine mammals)

3. cooling by evaporation

4. behavior

5. hormones

acclimatization

Adjust to new environment over a few daysGrow thicker furChange metabolic rateEctotherms: change at cellular level: make different

enzymes Change proportions of sat/unsat fats Heat-shock proteins: protect other proteins from

denature

Torpor

Adaptation: decreased activity & metabolism

Hibernation

Estivation: summer torpor