1
Q
homeostasis
A
maintenance of internal environment of the organisms
- variable are kept within preset limits despite fluctuations in the external environment
2
Q
endocrine system mechanism [6]
A
- a stimulus is received (eg. high blood glucose level)
- use of hormones (eg. insulin)
- secreted into the blood
- transported to target tissues (eg. liver cells)
- hormone changes the conditions of the tissue (eg. take in glucose and convert to glycogen)
- the change is monitored through feedback (mostly negative feedback)
3
Q
what secretes insulin and glucagon
A
Islets of Langerhans in the pancreases
4
Q
what cells synthesise and secrete glucagon
A
alpha cells
5
Q
what cells synthesise and secrete insulin
A
beta cells
6
Q
type 1 diabetes
A
- beta cells are destroyed by their own immune system
- cant produce the sufficient amount of insulin
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
8
Q
type 2 diabetes
A
lack of insulin receptors or glucose channels on cell membranes
9
Q
what is body temp detected by
A
thermoreceptors
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
11
Q
heat generation
A
- hypothalamus secretes thyrotropin releasing hormone (TRH)
- pituitary gland receives this chemical signal and releases thyroid stimulating hormone (TSH)
- increased thryroxin = increase metabolic rate and heat generation
12
Q
thyroxin
A
secreted by the thyroid gland when it receives thyroid stimulating hormone
13
Q
thyroxin increase temp
A
cooling- trigger more thyroxin to be secreted
- increases metabolic rate of cells and increases body temperature
14
Q
consequence of lack of thyroxin
A
hypothyroidism
- goiter (thyroid enlarges to try and capture iodine)
15
Q
muscles when cold
A
- muscles contract → movement → generates heat
16
Q
brown fat contains
A
a lot of mitochondria
- all energy is transformed into heat rather than producing atp
17
Q
when body is overheated
A
vasodilatation- arterioles 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
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
19
Q
arterioles
A
branches of arteries that supply blood to part of an organ
20
Q
what are walls of arterioles
A
ring of muscle
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
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
23
Q
hormone in kidney + function
A
ADH
osmoregulation
24
Q
excretion
A
removal from the body of waste production of metabolism
25
why is defacation not excretion
not waste of metabolism
26
what does urine contain
water
salt
urea
27
renal capsule function
ultrafiltration
28
renal artery function
blood pressure so blood goes in
29
what cant go through in ultrafiltration (from blood to urea)
red blood cells
platelets
proteins
30
what can go thru (from blood to urea) [6]
water
urea
glucose
sodium ions
chloride ions
amino acids
31
where can u find the substances that go from blood to urea
glomerular filtrate
32
microvilli function
increase surface area for diffusion
33
why is the movement slow around the convoluted tubule
more time to reabsorb nutrients
34
why proximal convoluted tubule cell has lots of mitochondria
active transport to reabsorb all wanted nutrients
= ATP production
35
proximal convoluted tubule function
selective reabsorption in the kidney
36
why diabetes occur
not enough glucose channels open to reabsorb to urine would have glucose
37
what does it mean when there is protein in urine
something wrong with the glomerulus
38
why doesnt burst of high pressure
basement membrane restricts the passage of blood cells and proteins
39
afferent arteriole function
brings blood to the nephron to be filtered
40
efferent arteriole
removes blood from nephron (except for filtered components)
41
glomerulus function
capillary tuft where filtration occurs
42
bowman's capsule function
first part of nephron where filtrate is collected
43
proximal convoluted tubule function
where selective reabsorption occurs
44
loop of Henle function
important for establishing a salt gradient in the medulla
45
distal convoluted tubule function
final site of selective reabsorption
46
collecting duct function
feeds into ureter and where osmoregulation occurs
47
vasa recta function
blood network that reabsorbs components from the filtrate
48
what happens when ur dehydrated
high adh
high reabsorption of water back into the blood
49
hypothalamus function
detects how hydrated blood is then signals to pituitary gland
50
how collecting duct reabsorbs
affects aquaporin so water go through plasma membrane faster
51
what are aquaporin
protein channels for water
52
aquaporin function
allows water pass through the plasma membrane faster
53
movement through aquaporins
facilitated diffusion so no energy involved
54
why cant water go thru the aquaporins fast
polar
55
what happens when adh increases
gene expression of aquaporin on the collecting duct → more water is reabsorbed → urine becomes more concentrated
56
what happens to aquaporins when there is too much water
aquaporins will break down
57
why is a countercurrent needed
because diffusion will cause it to reach an equilibrium to maintain a concentration gradient
58
water movement in collecting duct (to where + using what)
from collecting duct to capillaries by osmosis
59
how blood supply changes
- 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
shunt vessels function
direct blood directly from arterioles to venules
61
vasodilation
relaxation of circular muscle in arterioles (widening of the lumen)
bio
flashcards
Decks in class (40)
# Cards
-
a1.1- water24
-
a1.2- nucleic acids28
-
a2.1 origin of cells (hl only)14
-
a2.2- cell structure42
-
organelles44
-
a2.3- viruses20
-
a 3.1 diversity of organisms12
-
a3.2 classification and cladistics8
-
a4.1 evolution and speciation42
-
b1.1 carbohydrates and lipids86
-
b1.2 proteins84
-
b2.1 membranes and membrane transport66
-
b2.2- organelles and compartmentalisation34
-
b2.3- cell specialisation31
-
b3.3- muscle and mobility35
-
b3.1 gas exchange46
-
b3.2 transport41
-
plant transport34
-
b4.1 adaptation to environment18
-
b4.2 ecological niches41
-
c1.1- enzymes and metabolism73
-
c1.2- respiration78
-
c1.3- photosynthesis82
-
c2.1 chemical signalling61
-
c2.2 neural signalling46
-
c3.1 integration of body systems82
-
c3.2 defence against disease44
-
c4.1 populations and communities17
-
c4.2 transfer of energy and matter25
-
d1.1 dna replication64
-
d1.2 protein synthesis67
-
d2.1 cell and nuclear division75
-
meiosis11
-
d2.3 water potential12
-
d1.3 mutation and gene editing14
-
d3.1 reproduction145
-
d3.2 inheritance42
-
d3.3 homeostasis61
-
d4.1 natural selection31
-
ecology rwe70
