Chapter 40: Animal Form & Function
Animal Phylogeny
 Domain Eukarya, Kingdom Animalia, Phylum Chordata
 Subphylum Vertebrata – internal skeleton & jaw of bone/cartilage, ventral heart, large liver
 Superclass Tetrapoda – 4 limbs w/ digits, lung respiration
 Class Mammalia – endotherm, mammary glands, fur, internal fertilization, coelom divided by diaphragm
(thoracic & abdominal cavity)
 Subclass Eutheria – internal development of young, placenta
 Order Primates – opposable thumb, radius rotates over ulna, rotating shoulder, stereoscopic vision
 Family Hominidae – rounded skull, bipedalism, foramen magnum location
 Genus Homo – large brain, tool making, absence of bony crest
 Species Sapiens – brain size, skeletal components
Form & Function
 Both closely related
 Anatomy – studies biological form of an organisms
 Physiology – studies biological functions in an organism
Size & Shape
 Physical laws constrain strength, diffusion, movement, & heat exchange
 Convergent evolution reflects different species’ adaptations to similar challenges
Exchanges w/ Environment
 Nutrients, waste, gases dissolve in aqueous solution & diffuse across cell membrane
o Amount proportional to volume (Large cell = Large needs)
o Rate proportional to surface area
 Animals have interstitial fluid so all cells can exchange
Animal’s Heirarchy
 Cell-Tissue-Organ-Organ System
 Cell Junctions
o Tight junctions – 2 membranes pressed together; prevents interstitial fluid leaks
o Desmosomes (anchoring) – fasten cells together into strong sheets
o Gap junctions (communicating) – provide cytoplasmic channels b/w 2 cells
 Four main tissues:
o Epithelial Tissue
 Sheets of cells that cover outside of body, line organs & body cavities
 Cells held by tight junctions
 Function as barrier to fluid loss, pathogens, & mechanical injury
 Epithelial Forms
 Shapes: Cuboidal (cubes), columnar (bricks on end), or squamous (floor tiles)
 Arrangement: simple (single cell layer), stratified (multiple cell layers), or
pseudostratified (single cell layer of varying length)
 Tissue Examples
 Stratified Squamous
o Multi-layered tiles
o Outer skin, lining of openings
 Simple Squamous
o Single layer tile
o Blood vessels & lung air sacs
 Pseudostratified
o Single layer of varying shapes
o Trachea – mucous & cilia
 Simple Columnar
o Single layer bricks
o Secretion & Active Absorption (e.g. lines the intestines)
 Cuboidal
o Single layer of cubes
o Specialized for secretion (e.g. Thyroid, Salivary, Kidney tubules)
o
Connective Tissue
 Sparse cells scattered thru abundant extracellular matrix
 Holds tissues & organs together, body transport fluids, energy reserves, organ cushion,
fight invading pathogens
 Matrix made of 3 fiber types:
 Elastic – stretch/return to shape
 Collagenous – strength
 Reticular – join diff. tissues
 Tissue types classified by matrix
 Loose Connective (most common)
o Binds epithelia to other tissues & holds organs in place, few fibers
 Fibrous Connective
o Tendons (muscle to bone) & ligaments (bone to bone), many fibers
 Bone
o Ca, Mg, PO43- form a hard mineral extracellular matrix
 Blood
o Plasma, RBCs, WBCs, Platelets
 Cartilage
o Cells secrete protein-carb complex that is strong & rubbery
 Adipose
o Stores fat (fuel), cushions organs, insulates organism
o Muscle Tissue
 Responsible for body movement (voluntary & involuntary)
 Long (often multi-nucleated) cells w/ actin & myosin
 Three types:
 Skeletal Muscle (striated)
o Attached to bones by tendons
o Voluntary movement
 Smooth Muscle (non-striated)
o Digestive tract, arteries, urinary bladder
o Involuntary actions
 Cardiac Muscle (striated)
o Cause heart contraction
o Nervous Tissue
 Receipt, process, transfer of information
 Neurons – basic nerve cell (Axon, Dendrites, Soma)
 Glial Cells – support neurons (nourishment, make myelin sheath, insulation, structure)
Coordination & Control
 Harp Seal Dive – slows heart rate, collapses lungs, lowers body temp, propels itself w/ back flippers
 Messages must be sent across long distance to coordinate physiology (e.g. homeostasis)
 Hormonal Messages
o Hormone – chemical messenger
 Secreted by endocrine organ into blood stream
 Travels everywhere, causes response from cells w/ receptor
o Endocrines – hypothalamus, pituitary, thyroid, pancreas
 Neural Messages
o Long chains of neurons pass electrical & chemical message to specific location
o Received by 4 cell types – nerve, muscle, endocrine, exocrine
o Neuron Anatomy
 Dendrites – receive message
 Soma – body w/ nucleus & organelles
 Axon – long extension transmitting electrical message, covered by myelin sheath
 Synapse – gap in b/w cells
 Neurotransmitter pass over synapse, bind to receptor, message sent on

Messaging Strategies
o Neural – Extremely fast moving
 Better for immediate & rapid responses (motor system)
o Hormonal – Slow, often long-lasting
 Better for gradual changes affecting whole body (growth, development, digestion,
metabolism, repro.)
Homeostasis
 Negative feedback loops that maintain stable condition in body
 Blood Sugar – pancreas, liver, insulin, glucagon
 pH blood (7.4) – RBCs, carbonic acid, breathing
 O2 level – breathing, heart rate, vessel size
 Thermoregulation
o Heat Exchange Processes
 Radiation – electromagnetic radiation emitted
 Convection – transfer of heat thru liquid/gas
 Conduction – transfer of heat via contact
 Evaporation – water evaporation absorbs heat (cools surface)
o Metabolic Heat
 Metabolism produces excess heat during reactions
 Can be increased to produce more heat
 Shivering = increased muscle activity, increased metabolism
 Some have hormones to turn on metabolism for only heat
o Integument System
 Skin, fur, hair
 ‘Raising fur’ slows air flow across skin, retains heat
 Goose bumps remnant of this
 Insulation – adipose & blubber
 Blubber – very thick, resists heat loss in water (50-100x)
 Sweat Gland – evaporative cooling
o Circulatory System
 Vessels near environment can dissipate & absorb heat
 Vasodilation – vessels enlarge, release heat
 Vasoconstriction – vessels shrink, retain heat
o Behavioral Features
 Hot – seek shade or orient body to minimize heat absorption
 Cold – seek sunlight, stretch/ expand body to absorb heat
 Migration to warmer region
 Bees huddle together & beat wings (increase metabolism)
 Hibernation
o Human Thermoregulation controlled by hypothalamus