Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > Homeostasis (16) > Flashcards

Homeostasis (16) Flashcards

(58 cards)

Start Studying
1
Q

List the 3 important reasons for homeostasis

A

Keeps internal environment constant

Ensures cells function properly and avoid damage

Helps an organism respond and adapt to internal changes

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

Define homeostasis

A

Maintenance of a stable internal environment within restricted limits of an organism.

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

List the 3 controller mechanisms

A

Receptors- detect stimuli

Coordinators- interpret information

Effectors- muscles and glands

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

List 4 examples of negative feedback

A

Maintenance of blood glucose

Blood pH

Temperature

Water regulation

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

Describe the process of negative feedback (3)

A

Receptors detect change in one direction ]

Triggers effectors to produce response reversing initial change

Return to normal

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

Give 2 examples of positive feedback

A

Blood Clotting
Childbirth and oxytocin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List the steps of positive feedback (3)

A

Initial change occurs

Effectors stimulated and enhance change

Change continues until end point met

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Role of endocrine system

A

Uses hormones to send information about changes in environment around the body bringing about a response.

Eg. Pituitary gland, pancreas and adrenal glands

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

Role of hormones

A

Chemical messengers that bind to specific receptors stimulating target cells to respond to

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

What are steroid hormones

A

Lipid soluble
Bind to receptor molecule in cytoplasm (transcription factor)

Eg. Oestrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are non steroid hormones?

A

Water soluble
Bind to receptors on cell membrane

Eg, adrenaline

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

What is the 2nd messenger model?

A

Hormone (1st) triggering formation of 2nd messenger inside the cell.
Activates enzyme to carry out a function.

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

Example of 2nd messenger model

A

Adrenaline
Making glucose available via glycogenolysis (glycogen to glucose in liver cells)

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

Describe the 8 steps of the 2nd messenger model

A

1: adrenaline binds to receptor on cell membrane of liver cells
2: binding causes protein to change shape activating G protein
3: activates adenylyl cyclase
4: adenylyl cyclase converts ATP-cAMP
5: cAMP acts as a 2nd messenger to protein kinase via phosphorylation
6: protein kinase activates enzymes catalysing glycogen to glucose
7: glucose out of liver via facilitated diffusion into blood
8: increases blood glucose concentration (respiration)

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

Role of pancreas in regulating blood glucose levels

A

Islets of langerhans

Beta cells: secrete insulin
Alpha cells: secrete glucagon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when blood glucose levels increase? (5)

A

Beta cells secrete insulin
Inhibition of alpha cells
Increased glucose uptake
Increased respiration

Glycogenesis (glucose to glycogen)

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

What happens when blood glucose decreases? (5)

A

Alpha cells secrete glucagon
Inhibition of beta cells
Reduced respiration

Glycogenolysis (glycogen to glucose)

Gluconeogenesis (glucose from amino acids and fats in liver)

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

What is diabetes

A

Improperly regulated blood glucose levels

Signs glucose in urine etc….

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Quickly describe Type 1 diabetes

A

Often due to autoimmune disease destroying beta cells Increased glucose

Leads to no insulin. Production

Typically develops in childhood

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

Treatment of type 1 diabetes

A

Blood glucose monitoring
Insulin injections or pumps
Pancreas transplant
Exercising regularly to regulate blood glucose

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

Describe type 2 diabetes

A

Beta cells do not produce enough insulin or body cells are resistant

Higher than normal blood glucose levels

Develops later in life

Associated with obesity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Treatment of type 2 diabetes

A

Physical exercise
Diet control
Insulin therapy
Meds which increase cell sensitivity to insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the anatomy of the kidneys (draw)

A

Renal cortex
Renal pelvis
Renal medulla
Renal artery
Renal vein
Ureter.

Fibrous capsule

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

How to kidneys receive and return blood?

Study These Flashcards
A

Receive oxygenated blood from renal artery and renal vein returns filtered blood to heart via vena cava.

25
What is filtrate?
Material initially formed from blood
26
Bowman’s capsule structure
Surrounds glomerelus and contains podocytes
27
Proximal convoluted tubule (PCT) role
Reabsorbs useful substances eg. Water
28
Loop of henle role
Creates high solute gradient in medulla
29
Distal convoluted tubule (DCT) role
Fine tune water balance by re absorbing water into surrounding capillaries
30
Collecting duct role
Collects filtrate from multiple nephrons
31
Afferent arteriole role
Supplies blood to glomerelus
32
What is the glomerelus
Blood vesicle
33
Role of efferent areteriole
Carries blood away from glomerelus
34
What is ultrafiltration?
Process in which small molecules eg. Water, glucose, urea are filtered out the blood. In Bowman’s capsule forming glomerelar filtrate
35
List the process of ultrafiltration (6)
Blood via afferent areteriole Blood leaves via efferent areteriole (maintaining hydrostatic pressure) High pressure forces molecules out the blood through pores in endothelium. Molecules out basement membrane (collagen acts as a selective filter) Molecules move through bowman’s capsule (podocytes) with extensions (pedicels) which wrap around capillaries. Filtered fluid collects in bowman’s capsule.
36
What is glomerelar filtrate (in filtrate and stuff that stays in blood)
Substances in the filtrate eg. Water salts glucose and urea Remain in blood eg. Platelets, blood cells and proteins
37
Adaptations of the proximal convoluted tubule (PCT)
Microvilli increase SA Basal in folding increase SA Mitochondria provide ATP Cotransporter proteins transport from filtrate to cells
38
Process of reabsorbtion in PCT (4)
Na+ actively transported back into capillaries reducing Na+ concentration in epithelial cells lining the PCT. Na+ moves from PCT lumen into epithelial cells down a concentration gradient Na+ co transported with glucose into epithelial cells These reabsorbed molecules diffuse into blood capillaries
39
What is the role of the DCT?
Make final adjustments to filtrate by reabsorbing water and salts Reabsorption of useful substances via AT Alteration of DCT membrane permeability regulating reabsorption of water and solutes Regulation of blood pH by selective reabsorption of ions
40
Stricture of the loop of henle
Descending limb- 1st section which is narrow, permeable to water and impermeable to ions Ascending limb- 2nd section which is wider, impermeable to water and permeable to ions
41
1st step in water reabsorption in loop of henle
Water leaves descending limb down a concentration gradient via osmosis
42
2nd step in water reabsorption in loop of henle
Filtrate looses water down descending limb (lowest water potential in tip of loops of henle)
43
3rd step in water reabsorption in loop of henle
Water lost and reabsorbed into blood via osmosis
44
4th step in water reabsorption of loop of henle
Ascending limb impermeable to water but permeable to Na+ and Cl-
45
5th step of water reabsorption in loop henle
Na+ and Cl- diffuse out filtrate into interestrial space due to the low water potential
46
6th step in water reabsorption in loop of henle
This concentrates ions in then interestrial space in medulla making low water potential
47
7th step in water reabsorbtion in loop of henle
Na+ and Cl- AT out of the top of ascending limb as concentration in filtrate decreases as ascends
48
8th step in water reabsorption in loop of henle
Creates a water potential gradient in interestrial space
49
1st step of countercurrent multiplier
As filtrate moves down the collecting duct it loosed water (decreased water potential)
50
2nd step of countercurrent multiplier
Pumping ions out ascending limb (water potential of surrounding tissues even lower)
51
3rd step of countercurrent multiplier
Allows water to continue to move out filtrate down whole length of collecting duct
52
Allows water to continue to move out filtrate down whole length of collecting duct
53
Role of ADH
Produced in hypothalamus Stored in prosterior pituitary gland Targets cells lining distal convoluted tubules (DCTs)
54
List ADH mechanism (5)
ADH attaches to receptors on surface of cells in DCT and collecting duct Triggers activation of enzyme phosphorylase Water channels proteins (aquaphorins) being integrated in cell surface membrane Water moves through aquaphorins via osmosis from DCT and collecting duct into interestrial space Water reabsorbed into the blood
55
Is ADH mechanism positive or negative feedback
Negative feedback
56
What responds to changes in blood water or ion levels?
Osmoreceptors in hypothalamus
57
Describe the process when lack of water in blood (5)
Water from osmoreceptors into the blood via osmosis. Osmoreceptors shrink detecting water decrease (water potential) produce ADH Nerve signals prompt release of ADH from prosterior pituitary gland (ADH—KIDNEYS) Increase in aquaphorins in DCT and collecting ducts More water reabsorbed Urine more concentrated
58
Describe the process of excess water in blood
Reverse of lacking water

Biology (13 decks)

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