chapter 33: animal form and function

bilateral symmetry and an example of it

bilateral symmetry and an example of it

• totally equal

• most fit to be agile

• ex. humans

Radial symmetry

• each quadrant looks the same

• ex. sea anemone

Assymetry

• no symmetry

• ex. sea sponge

Dorsal

top

Ventral

bottom

Anterior

front

Posterior

back

Sagittal

right and left

Frontal

front and back

Transverse

upper and lower

Convergent evolution

The process whereby distantly related organisms independently evolve similar traits to adapt to similar necessities

Animal cavities

general form of the vertebrate body consist of a series of cavities

Epithelial tissue

• acts like a barrier

• lets some things in and keeps some things out

• covers every major surface of the vertebrate body, both inside and outside

Simple epithelium

one layer thick

Squamous epithelium

skin, lining of lungs

Stratified squamous epithelium

• many cell layers thick and regenerates rapidly because it covers surfaces of general wear and tear

Cuboidal epithelium

• lining of kidney tubules

Columnal epithelium

• lining of stomach lungs

• active in secretion and absorption (ex. cilia)

Transitional epithelium

• lining of bladder

• expands and contracts

Carcinomas is the cancer of...?

Epithelial cell cancers

Smooth muscle

• lacks striation

• involuntary control

Cardiac muscle

• smaller, interconnected cells with a single nucleus

• good conductors of electrical current

• involuntary control

Skeletal muscle

• contains multiple nuclei and attached to tendons and bones with multiple stirations

Two kinds of regular connective tissue

Loose and Dense

Loose connective tissue

• product of fibroblasts scattered within clear fluid that holds blood vessels and epithelia in place

• provides scaffolding!!!!

Regular dense connective tissue

• collagen fibers lined up in parallel

• makes up tendons and ligaments

• stress forces only go in one direction

Tendons

muscle to bone

Ligaments

bone to bone

Irregular dense connective tissue

• collagen fibers that have many directions found in skin

• this means that there are multiple stress forces

Neurons

• nerve cell

• produces and conducts electrochemical impulses

Cell body

contains nucleus

Dendrites

• thin, branchy extensions that RECEIVE neural stimulation

• conducts electrical currents towards the cell body

Axons

• extensions that allow nerve impulses from a neuron to travel AWAY so they can be received by other neurons

Homeostasis

aims to keep internal conditions around a set point

Feedback loops

the mechanism that kicks in when conditions stray too far away from a set homeostatic condition

Negative feedback loop and example

• reverses the direction of change

• most feedback loops are negative!!!!

• ex. glucose levels

positive feedback loop and example

• maintains and sometimes strengthens the response of a stimulus

• ex. oxytocin during pregnancy

Set point alteration and example

• when the normal set point is adjusted to a new setpoint which becomes the new normal

• ex. blood pressure in correlation to age

Acclimization and example

• changes in one organ system to maintain a set point in another organ system

• ex. altitude

Thermoregulation

Maintaining a constant internal temperature to keep enzymes working efficiently

Ectotherm

Rely on external temperature to maintain their body temp

Endotherm

Rely on internal sources to maintain relatively constant temperature

surface area to volume ratio

• ratio of a cell's outside area to its internal volume.

• small animal has a large surface area compared to the volume, thus radiates heat much quicker. A large animal has a large surface area AND a large volume

Since larger animals have a larger body mass, then ....

it needs greater chemical energy

Since the metabolic rate is higher in smaller animals, the energy requirement for each gram of body mass is ...

higher