2: homeostasis, thermoregulation, and animal tissues

organisms use homeostasis to…

maintain a steady state/internal balance regardless of external environment

what in humans is maintained at a constant lvl?

body temp.(37°C), blood pH(7.40), and glucose concentration

what does homeostasis in animals rely largely on?

negative feedback which helps return variable to normal range

what does positive feedback do?

amplifies a stimulus and doesn’t contribute to homeostasis in animals

what do mechanisms of homeostasis do?

moderate changes in the internal environment

fluctuations above/below a set point serve as a…

stimulus that are detected by a sensor triggering a response

what does the response of a give variable do?

returns the variable to the set point

what type of feedback controls blood sugar lvls ?

a negative feedback loop bc insulin lowers blood/glucose lvl

what type of feedback is used during the birth of a human infant?

positive feedback bc the baby sends nerve impulses to the brain which releases oxytocin causing the uterus to contract

acclimatization

adjust to changes in external environment due to homeostasis

what is an example of acclimatization?

when an animal migrates to a higher altitude than which it’s accustomed

higher altitude=

lvl of oxygen decreases

at higher altitude blood cells must?

increase O2 made transferring it to the tissues

in order to adjust to lower oxygen lvls what must the body do?

increase the # of red blood cells circulating in the blood to ensure adequate oxygen delivery to the tissues

what must be done to keep enzymes efficient and avoid denaturation?

must maintain a relatively constant internal temp.

thermoregulatory is controlled by ?

the hypothalamus

hypothalamus

region in the brain that controls the set point of body temp.

what is heat exchanged by ?

radiation, convection, conduction, and evaporation

radiation

electromagnetic heat waves

convection

remove heat from surface area of dry skin as air passes it

conduction

transfer of energy, such as heat or an electric charge, through a substance

evaporation

water change state from liquid to gas (ex: humans sweating to cool us down)

what does heat regulation in mammals involve ?

integumentary system

integumentary system

skin, hair, and sweat glands

what are five adaptations that help animals thermostate?

1. insulation

2. circulatory adaptations

3. cooling by evaporative heat loss

4. behavioral responses

5. adjusting metabolic heat production

what occurs during insulation ?

body temp increases

vasodilation occurs (blood vessels dilate)

blood flow to skin increases

sweating occurs and heat is lost

what occurs during cooling by evaporative heat loss?

body temp decreases

vasoconstriction occurs(blood vessels constrict)

blood flow to skin decreases and heat is retained(shivering)

what are behavioral responses?

echo and endo

what is adjusting metabolic heat production?

muscle activity

what do honey bees do to thermoregulate ?

huddles tg during cold weather to retain heat

animals with thick fur/feathers have what for insulation?

an insulating layer of hair b/w their skin and internal organs

what are the 4 main types of animal tissues ?

epithelial tissues, connective tissues, muscle tissues, and nervous tissues

epithelial tissues fxn

like cavities and open spaces/surfaces

connective tissues fxn

connect tissues tg providing support

muscle tissues fxn

generate movement

nervous tissues fxn

generate and send electrical signals

what are epithelial tissues classified by?

# of layer and shape of cell

simple

single layer

stratified

multiple layers

what are the 4 epithelial tissues?

squamous

cuboidal

columnar

transitional

what describes squamous?

flat, irregular round shape

what describes cuboidal?

cube shaped, central nucleus

what describes columnar?

tall, narrow, nucleus toward base; tall, narrow, nucleus along cell

what describes transitional?

round, simple but appear stratified

location of simple squamous tissue?

lung alveoli and capillaries

location of stratified squamous tissue?

skin, mouth, and vagina

location of cuboidal tissue?

glands and renal tubes

location of simple columnar tissue?

digestive tract

location of psuedostratified columnar tissue?

respiratory tract

location of transitional tissue?

urinary bladder

fxn of squamous tissue

diffusion

fxn of cuboidal tissue

glands- secretion

renal tubules- filtration

fxn of columnar tissue

absorption and protection

fxn of transitional tissue

change from thick to thin as bladder fills

what are connective tissues derived from?

the mesoderm

connective tissues consist of…

cells (fibroblasts) embedded in a non-cellular gel-like substance (ground substance)

what do connective tissues contain a combination of?

collagen for strength, elastic for flexibility, and reticular fibers for support

muscle tissue was derived from?

the endoderm

what are the 3 kinds of muscle tissues?

skeletal

smooth

cardiac

what muscle tissues are involuntary?

smooth and cardiac

what muscle tissues are voluntary?

skeletal

what muscle tissues are striated?

skeletal and cardiac

what does the striated appearance of muscle come from?

actin and myosin

what muscle tissue has no striations?

smooth

what muscle tissue has intercalated discs?

cardiac

intercalated discs fxn

rejoin adjacent cardiac muscle and helps in pairing impulses

nervous tissues was derived from?

the ectoderm

nueron

main cell of the nervous system that receive and transmit electrical impulses

cell body

large structure w a central nucleus

dendrites

projections from cell body socialized on receiving input

axon

projection from cell body specialized on transmitting impulses

what are the glial cells of the neuron?

astrocyte and oligodendrocyte

astrocyte

regulate the chemical environment of the nerve cell

oligodendrocyte

insulate axon so the electrical serve impulse is transferred more efficiently

axon terminals

ending of axons which make synaptic contacts w other nerve cells