Chapter 16 - Animal Structure

Radial Symmetry

arranged around central axis, bisected into two equal halves

Bilateral Symmetry

body has right and left halves that are mirror images

3 ways bilateral symmetry can be sectioned into 3 planes:

1. Front/Coronal - separates front and back

2. Transverse - cross-section of a stem

3. Saggital - divides left from right

   1. midsaggital plane - left and right sides are mirror images

Most small unicellular organisms get nutrients through …

diffusion

Cell size is constrained by …

surface area-to-volume ratio

Larger organisms don’t have larger cells, they just have ___ cells

more

Basal Metabolic Rate

average amount of energy used by an organism in a non-action state

Excess energy is given off as…

heat

Metabolic Rate

amount of energy expanded by an animal over a specific time

Ectotherms

dependent on environment for body heat

Endotherms

maintain a relatively constant body temperature (fat, hair, feathers)

In Endotherms:

1. smaller organisms have a higher basal metabolic rate

2. active animals have a higher basal metabolic rate

Acclimatization

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

Positive Feedback Loop

maintains and potentially strengthens the response to stimulus

Negative Feedback Loop

counteracts internal changes (reverses the direction of the change)

Most biological systems are on ….

negative feedback loops (temperature, glucose, pH, and blood calcium levels)

Hypothalamus job

controls thermoregulation

4 ways temperature is maintained:

1. radiation - heat released

2. convection - fan o rbath (air/water removing heat)

3. conduction - heat transfer from surface (warm/cool rock)

   1. evaporation - sweating

Parazoa

lack of defined tissues and organs, can diseggregate and aggregtae their cells

Eumetazoa

have distinct and well defined tissues, irreversible differentiation of most cell types

4 types of animal tissues

1. connective tissues

2. epithelia

3. muscles

4. neurons

Connective tissues

together, provide support (consists of cells, fibers, and gel-liek substance)

Epithelia

cover outside of organs and structures, classified by number of layers and shape of the cell

Muscles

generate movement

Neurons

generate and send electrical signals

Squamous Epithelial

simple: lung alveoli, capillaries

stratified: skin, mouth, vagina

Simple Squamous

Stratified Epithelial

Simple Cuboidal

Stratified Cuboidal in testis

Cuboidal Epithelial where is it found?

glands and renal tubes (kidneys)

Columnar Epithelial where is it found?

digestive tract, respiratory tract

Simple Columnar

Stratified Columnar

3 types of muscle tissues

1. skeletal - voluntary, striated, multinucleate

2. smooth - involuntary, no striations

3. cardiac - involuntary, striated, intercalated discs

Gilal Cells (neuroglia)

supporting cells of the nervous system

Projections from the cell body are either:

1. dendrites (specialized in receiving input)

2. a single axon (specialized in transmitting impulses)