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Biology Unit 3 > Homeostasis and Kidney 3.7 > Flashcards

Homeostasis and Kidney 3.7 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is homeostasis?

A

Homeostasis is the mechanism that maintains a constant internal environment.

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2
Q

What are examples of homeostasis?

A

Osmoregulation
Thermoregulation
Glucose regulation

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3
Q

What are the two main functions of the kidney?

A

Removal of nitrogenous metabolic waste from the body.
Osmoregulation, the mechanism by which the balance of water and dissolved solutes is regulated.

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4
Q

What is urea?

A

A poisonous chemical made by the liver.

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5
Q

What is the function of the ureter?

A

Narrow tubescarry urine from the kidneys to the bladder

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6
Q

What is the function of the bladder?

A

The bladder’s wallsrelax and expand to store urine, and contract and flatten to empty urine through the urethra.

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7
Q

What is the function of the urethra?

A

This tubeallows urine to pass outside the body.

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8
Q

What is the function of the renal vein?

A

The main blood vessel thatcarries blood from the kidney and ureter to the inferior vena cava.

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9
Q

What is the function of renal artery?

A

The renal arteriescarry a large volume of blood from the heart to the kidneys.

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10
Q

Where does ultrafiltration take place?

A

Between the glomerulus and the bowman’s capsule.

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11
Q

What is the first step in ultrafiltration?

A

The afferent arteriole is wider than the efferent arteriole which allows for the glomerulus to have a high blood pressure.

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12
Q

What is the second step in ultrafiltration?

A

The proteins travel to the basement membrane which are both negatively charged so they repel each other.

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13
Q

What is the last step in ultrafiltration?

A

After making it through the basement membrane, they make it to the podocytes which have filtration slits in between the pedicles.

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14
Q

What is selective reabsorption?

A

The process of which useful products such as glucose and salts are reabsorbed back into the blood.

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15
Q

How is water reabsorbed?

A

Osmosis from a high concentration to a low concentration through a semi permeable membrane. This requires no energy.

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16
Q

How are sodium ions reabsorbed?

A

Facilitated diffusion into the cell from the glomerular filtrate requiring the sodium potassium pump. From the pump to the blood, it used active transport using ATP.

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17
Q

How are chlorine ions reabsorbed?

A

Facilitated diffusion from a high concentration to a low concentration.

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18
Q

How are glucose and amino acids reabsorbed?

A

Facilitated diffusion. Glucose and amino acids diffuse with sodium ions. The glucose is transported through active transport from the proximal convoluted tubule into the blood.

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19
Q

What is negative feedback?

A

Self-regulatory mechanisms return the internal environment to the optimum when there is a fluctuation.

20
Q

What is positive feedback?

A

A fluctuation which triggers changes that result in an even greater deviation from the normal level.

21
Q

What are receptors?

A

Specialised cells located in sense organs that detect a specific stimulus.

22
Q

What are effectors?

A

Muscles or glands which enable a physical response to a stimulus.

23
Q

What is the role of the coordinator?

A

Coordinates information from the receptors and sends instructions to the effectors.

24
Q

What is osmoregulation?

A

The regulation of the water potential of body fluids by the kidneys.

25
Q

Why is osmoregulation important?

A

It prevents lysis or the cell shrinking when osmosis takes place.

26
Q

What is excretion?

A

The process of removing metabolic waste from an organism.

27
Q

How are amino acids excreted?

A

They are deaminated in the liver to form ammonia which is converted to urea and is transported into the blood plasma and eliminated by the kidneys.

28
Q

What does the renal artery do?

A

Supplies blood to the kidneys.

29
Q

What does the renal vein do?

A

Drains blood from the kidneys.

30
Q

Where is the nephron found?

A

In the medulla and cortex.

31
Q

What is ultrafiltration?

A

The removal of small molecules, water and ions from the blood in the glomerulus of the kidney at high pressure.

32
Q

What is the process of ultrafiltration?

A

It takes place in the bowman’s capsule where high hydrostatic pressure in the glomerulus forces small molecules such as urea and glucose out of capillary fenestrations against the osmotic gradient. It then reaches the basement membrane which acts as a filter keeping blood cells and large molecules such as proteins in the capillary.

33
Q

Why is there a build up of pressure in the glomerulus?

A

Afferent arteriole leading into the glomerulus is wider than the efferent arteriole taking blood from the glomerulus.

34
Q

How are cells of the bowman’s capsule adapted for ultrafiltration?

A

Fenestrations between epithelial cells of capillaries. Fluid can pass between and under folded membrane of podocytes.

35
Q

Where does selective reabsorption take place?

A

In the proximal convoluted tubule.

36
Q

What is the loop of Henle?

A

A loop consisting of a descending and ascending limb surrounded by blood capillaries.

37
Q

What is the function of the loop of Henle?

A

It creates a low water potential in the medulla enabling the reabsorption of water.

38
Q

What happens in the loop of Henle?

A

Active transport of sodium and chlorine ions out of the ascending limb which decreases water potential of interstitial fluid. Movement of water out of descending limb by osmosis. Water potential of filtrate decreases going down the descending limb.

39
Q

What is an endocrine gland?

A

A gland of the endocrine system that secretes hormones directly into the bloodstream.

40
Q

How is the concentration and volume of urine controlled?

A

By the secretion of anti-diuretic hormone.

41
Q

What is the role of the hypothalamus in osmoregulation?

A

Osmoreceptors in the hypothalamus detect the concentration of the blood plasma so hypothalamus secretes ADH.

42
Q

What iss the role of the posterior pituitary gland in osmoregulation

A
43
Q

What is the role of the posterior pituitary gland in osmoregulation?

A

Stores and secretes the ADH produced by the hypothalamus.

44
Q

How does ADH affect the reabsorption of water from the kidney tubules?

A

ADH causes insertion of aquaporins into the plasma membranes of cells of the DCT and collection duct which increases permeability. more water is reabsorbed so more concentrated urine is produces.

45
Q

Effects of kidney failure.

A

Build up of toxic waste products, fluid accumulation, hypertension and anaemia.

Biology Unit 3 (8 decks)

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