Homeostasis

Question 1

homeostasis

Answer 1

regulation of the bodily internal enviroment at or near a stable level
requires a lot of energy

Question 2

homestatic process

Answer 2

external changes -> homeostatic mechanism -> internal changes

Question 3

external changes

Answer 3

large changes over time

Question 4

internal enviroment

Answer 4

small changes over time

Question 5

set point/set range

Answer 5

the level at which the condition controlled by a homeostatic pathway is to be maintained

Question 6

set point may involve

Answer 6

negative feedback
positive feedback
feedforward

Question 7

negative feedback

Answer 7

returns variable towards the set point/range
minimizes difference between actual level and the set point

Question 8

endotherm

Answer 8

heat comes from inside

Question 9

ectotherm

Answer 9

heat comes from outside

Question 10

homeotherm

Answer 10

need constant temperature
goes with endotherm

Question 11

heterotherm

Answer 11

allows variance for level of temp
goes with ectoter,

Question 12

thermogenesis

Answer 12

processing of generating body heat
ectotherm might exihibit certain behaviours

Question 13

homestasis keeps physiological variables…

Answer 13

stable not constant

Question 14

skin temperature process

Answer 14

change in skin temp - hypothalamic centres for thermoregulation - motor neurons OR sympathetic nerves OR voluntary changes in behaviour - skeletal muscles, smooth muscle, sweat glands, or smooth muscle - muscle tone, vaso, sweating, piloerection

Question 15

core temperature process

Answer 15

central thermoreceptors in hypothalamus, abdominal organs, and elsewhere - hypothalamic centres for thermoregulation - onto the same process

Question 16

negative feedback maintains

Answer 16

a balance between heat loss and heat gain

Question 17

negative feedback heat look

Answer 17

body temp rises above set point - hypothalamus detects - cooling physiology triggered - boyd falls below set point - hypothalamus triggered - heating physiology - repeat

Question 18

hypothalamus example of negative feedback

Answer 18

hypothalamis stimulates anterior pituitary gland through TRH - TSH stimulates thyroid to make T3 and T4 - develops chemicals that interact with body tissue - increased T3 and T4 reduces hypothalamus activity
2. idione deficency = T3 AND T4 low = more TSH = overstimulate thyroid = more hypothalamus

Question 19

what can a low level of iodine cause

Answer 19

hypothyroidism - low levels of T3 and T4 = more hypothalamus = more TSH = thyroid gets larger

Question 20

negative feedback example endocrine - calcium

Answer 20

homeostasis (normal calcium level) - calcium levels in blood falls below normal limit - parathyroid glands are stimulated by low level - more PTH secreted - release calcium from bone to blood - calcium increases - patahyroid is inhibited - less PTH is secreted - less Ca released from bone to blood

Question 21

what does the kidney do in homeostasis

Answer 21

important in regular iodine levels

Question 22

kidney homeostasis

Answer 22

too much salt = less water in urine and more salt

Question 23

positive feedback

Answer 23

moves variable away from the set point
amplifies difference between actual level and set point
short term
increase or decrease a process quickly
shut off by negative feedback soon

Question 24

positive feedback example. - childbirth

Answer 24

brain triggers release of hormones from the pituatry gland (oxytocin), enter the blood and increase contractions, contractions tell brain to make hormones

Question 25

positive feedback example - rising phase of the nerve action potential

Answer 25

once a nerve signal reaches threshold potential an action potential is triggered even more

Question 26

feedforward

Answer 26

future needs are anticipated and physiology is adjusted in advance

Question 27

what happens during fever

Answer 27

temp increase in body temp cus of infectoin
foriegn bodies signal hypothalamas to increase temp set point
turns on immune system to help fight infection