Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bio > d3.3 homeostasis > Flashcards

d3.3 homeostasis Flashcards

1
Q

homeostasis

A

maintenance of internal environment of the organisms
- variable are kept within preset limits despite fluctuations in the external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

endocrine system mechanism [6]

A
  1. a stimulus is received (eg. high blood glucose level)
  2. use of hormones (eg. insulin)
  3. secreted into the blood
  4. transported to target tissues (eg. liver cells)
  5. hormone changes the conditions of the tissue (eg. take in glucose and convert to glycogen)
  6. the change is monitored through feedback (mostly negative feedback)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what secretes insulin and glucagon

A

Islets of Langerhans in the pancreases secrete these hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what cells synthesise and secrete glucagon

A

alpha cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what cells synthesise and secrete insulin

A

beta cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

type 1 diabetes

A
  • cant produce the sufficient amount of insulin
  • beta cells are destroyed by their own immune system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

why problem when blood glucose stays at a high level

A
  • only can use simple diffusion bc glucose is polar
    • too slow
  • not enough insulin- channels wont open
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

type 2 diabetes

A

lack of insulin receptors or glucose channels on cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is body temp detected by

A

thermoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where are thermoreceptors found

A
  • peripheral thermoceptors can be found in the skin
  • central thermoreceptors are found in the care of the body, including the hypothalamus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

heat generation

A

– hypothalamus secretes thyrotropin releasing hormone (TRH)
- pituitary gland receives this chemical signal and releases thyroid stimulating hormone (TSH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

thyroxin

A

secreted by the thyroid gland when it receives thyroid stimulating hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

thyroxin increase temp

A

cooling will trigger more thyroxin to be secreted, this increases metabolic rate of cells and increases body temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

consequence of lack of thyroxin

A

hypothyroidism
- goiter (thyroid enlarges to try and capture iodine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

muscles when cold

A
  • muscles contract to cause movement- generates heat
  • small, involuntary muscle contractions and relaxation (shivering) can be carried out to generate heat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

brown fat contains

A

a lot of mitochondria
- all energy is transformed into heat rather than producing atp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when body is overheated

A

vasodilatation- - circular muscle cells in the walls or arterioles (thinner than arteries but thicker than capillaries) supplying the skin relax → arterioles widen
- more blood flows to the skin → warms up to core temperature
- increased temp difference between skin and external environment causes more heat to be lost from the body
- only the amount of blood flowing through capillaries in the skin can be varied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

vasoconstriction

A
  • when circular muscle contracts- circumference of arteriole is reduced and lumen along the blood flows is narrowed
  • less blood flows to the region supplied by the arteriole
  • reduce heat loss- vasoconstriction of arterioles supplying the skin
  • less blood flows to capillaries in the skin and cools below core body temperature
  • with reduced temperature difference between the skin and external environment- less heat is lost from the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

arterioles

A

branches of arteries that supply blood to part of an organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are walls of arterioles

A

ring of muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

sweating

A
  • secreted by glands in the skin and passes through narrow ducts to the skin surface, where water in the sweat evaporates
  • solutes in the sweat (ions: sodium) left on the skin surface
  • water has a high latent heat of vaporisation so its evaporation causes significant cooling
  • blood flowing through the skin loses heat and can then cool other parts of the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

hair erection

A
  • air between the hairs acts as a thermal insulator
  • erector muscles can move the hairs to make the coat thicker and the insulating effect greater
  • human- only a few short hairs so erector muscles can still make the hairs stand up but they dont trap air well enough to insulate the body
  • goose-bumps: ineffectual response to cold
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

hormone in kidney + function

A

ADH
osmoregulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

excretion

A

removal from the body of waste production of metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

why is defacation not excretion

A

not waste of metabolism

26
Q

what does urine contain

A

water
salt
urea

27
Q

renal capsule function

A

ultrafiltration

28
Q

renal artery function

A

blood pressure so blood goes in

29
Q

what cant go through in ultrafiltration (from blood to urea)

A

red blood cells
platelets
proteins

30
Q

what can go thru (form blood to urea)

A

water
urea
glucose
sodium ions
chloride ions
amino acids

31
Q

where can u find the substances that go from blood to urea

A

glomerular filtrate

32
Q

microvilli function

A

increase surface area for diffusion

33
Q

why is the movement slow around the convoluted tubule

A

more time to reabsorb nutrients

34
Q

why proximal convoluted tubule cell has lots of mitochondria

A

active transport to reabsorb all wanted nutrients
= ATP production

35
Q

proximal convoluted tubule function

A

selective reabsorption in the kidney

36
Q

why diabetes occur

A

not enough glucose channels open to reabsorb to urine would have glucose

37
Q

what does it mean when there is protein in urine

A

something wrong with the glomerulus

38
Q

why doesnt burst of high pressure

A

basement membrane that restricts the passage of blood cells and proteins

39
Q

afferent arteriole function

A

brings blood to the nephron to be filtered

40
Q

efferent arteriole

A

removes blood from nephron (except for filtered components)

41
Q

glomerulus function

A

capillary tuft where filtration occurs

42
Q

bowman’s capsule function

A

first part of nephron where filtrate is collected

43
Q

proximal convoluted tubule function

A

where selective reabsorption occurs

44
Q

loop of henle function

A

important for establishing a salt gradient in the medulla

45
Q

distal convoluted tubule function

A

final site of selective reabsorption

46
Q

collecting duct function

A

feeds into ureter and where osmoregulation occurs

47
Q

vasa recta function

A

blood network that reabsorbs components from the filtrate

48
Q

what happens when ur dehydrated

A

high adh
high reabsorption of water back into the blood

49
Q

hypothalamus function

A

detects how hydrated blood is then signals to pituitary gland

50
Q

how collecting duct reabsorbs

A

affects aquaporin so water go through plasma membrane faster

51
Q

what are aquaporin

A

protein channels for water

52
Q

aquaporin function

A

allows water pass through the plasma membrane faster

53
Q

movement through aquaporins

A

facilitated diffusion so no energy involved

54
Q

why cant water go thru the aquaporins fast

A

polar

55
Q

what happens when adh increases

A

gene expression of aquaporin on the collecting duct → more water is reabsorbed → urine becomes more concentrated

56
Q

what happens to aquaporins when there is too much water

A

aquaporins will break down

57
Q

why is a countercurrent needed

A

because diffusion will cause it to reach an equilibrium to maintain a concentration gradient

58
Q

water movement in collecting duct (to where + using what)

A

from collecting duct to capillaries by osmosis

59
Q

how does blood supply changes

A
  • adjusted using rings of circular muscle in the walls of the arterioles serving the organ
  • contraction of the rings of muscle causes vasoconstriction (narrowing of the lumen) and restricts blood flow
60
Q

shunt vessels function

A

direct blood directly from arterioles to venules

61
Q

vasodilation

A

relaxation of circular muscle in arterioles (widening of the lumen)

bio (39 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions