Homeostasis

Question 1

What is homeostasis?

Answer 1

This is maintaining a constant internal environment and reaching a ‘steady state’

Question 2

What are some conditions within the body that should be kept constant?

Answer 2

Body temperature
Blood pH
Water content of blood
Blood glucose concentration

Question 3

What homeostatic function is the kidney involved in?

Answer 3

Osmoregulation

Question 4

Why is homeostasis important?

Answer 4

Temperature regulation to avoid the denaturation of enzymes

Question 5

What is osmoregulation?

Answer 5

It helps to prevent lysis or crenation of cells

Question 6

What does crenation mean?

Answer 6

Shrivel or go wrinkly

Question 7

What is meant by the word ‘lysis’?

Answer 7

To split or burst

Question 8

What do homeostatic mechanisms use and why?

Answer 8

They use negative feedback to maintain a constant value

Question 9

What will happen to the corrective mechanism when the change is bigger?

Answer 9

The corrective mechanism becomes better

Question 10

When change occurs what automatically will appear?

Answer 10

A corrective mechanism

Question 11

What are 2 characteristics of the kidney?

Answer 11

Homeostatic organ
Involved in excretion

Question 12

What is excretion?

Answer 12

Removal of toxic waste products of metabolic processes from the body - urea is the most common

Question 13

What process is the kidney involved in?

Answer 13

Involved in osmoregulation

Question 14

What makes or causes urea?

Answer 14

The breakdown of excess amino acids and nucleic acids in the liver

Question 15

What makes or forms creatinine?

Answer 15

The degradation of a molecule involved in ATP generation

Question 16

What do kidneys help to maintain?

Answer 16

Water potential of body fluids

Question 17

What excretion are the lungs involved in?

Answer 17

The excretion of carbon dioxide

Question 18

What do the kidneys excrete?

Answer 18

Urea
Creatinine

Question 19

What is the role of the kidneys?

Answer 19

The removal of nitrogen containing waste products such as urea and creatinine

Question 20

Where does urine exit the body?

Answer 20

Via the urethra

Question 21

What muscle controls the flow of urine?

Answer 21

The sphincter muscle

Question 22

When excretory products enter the ureter where are they stored?

Answer 22

In the bladder

Question 23

What is a nephron?

Answer 23

The functional unit of the kidney

Question 24

How many nephrons are there per kidney?

Answer 24

1,000,000

Question 25

What 4 parts does each kidney consist of?

Answer 25

Bowman's capsule The proximal convoluted (coiled) tubule The Loop of Henle The distil convoluted tubule

Question 26

When nephrons join what do they form?

Answer 26

A collecting duct

Question 27

What is the point of the collecting duct?

Answer 27

Transfers fluid (urine) towards the renal pelvis

Question 28

What are the 2 stages that urine production occur in?

Answer 28

Ultrafiltration Reabsorption

Question 29

What happens during the stage ultrafiltration?

Answer 29

glomerular plasma is filtered into Bowman's capsule at high pressure. Filtrate contains both useful and toxic molecules

Question 30

What happens during the stage of reabsorption?

Answer 30

Useful substances are reabsorbed into the blood stream

Question 31

What are some useful substances that will have to be reabsorbed?

Answer 31

Glucose Amino acids

Question 32

What are some toxic molecules that are released through the urine?

Answer 32

Urea Creatinine

Question 33

What is the bowman's capsule also known as?

Answer 33

The filter

Question 34

What are the 2 layers that the Bowman's capsule consist of?

Answer 34

Epithelium - outer layer Squamous (thin) endothelium of the blood capillaries in the glomerulus - inner layer

Question 35

What way are the capsule epithelial cells arranged and what is their name?

Answer 35

Arranged in an irregular network and are called podocytes

Question 36

What are podocytes?

Answer 36

Footed cells

Question 37

What are found between the minor processes?

Answer 37

Filtration slits

Question 38

What do these filtration slits allow for?

Answer 38

The passage of all constituents of blood plasma but not blood cells

Question 39

What do pores allow for?

Answer 39

The passage of blood plasma, including proteins

Question 40

What is the role of the basement membrane?

Answer 40

To act as a barrier to plasma proteins

Question 41

What is the basement membrane also known as?

Answer 41

It is also the dialysing membrane responsible for ultra-filtration

Question 42

What is the proximal convoluted tubule involved in?

Answer 42

Involved in selection reabsorption

Question 43

What does the proximal convoluted tubule contain?

Answer 43

Cuboidal epithelial cells Numerous mitochondria Microvilli

Question 44

Why does the proximal convoluted tubule contain mitochondria?

Answer 44

For ATP synthesis, active transport and aerobic respiration

Question 45

Why does the proximal convoluted tubule contain microvilli and basal invaginations?

Answer 45

To increase the surface area for reabsorption

Question 46

What are the 2 stages of urine production?

Answer 46

Ultrafiltration Reabsorption

Question 47

What is ultrafiltration?

Answer 47

Glomerular plasma is filtered into Bowman's capsule at high pressure Filtrate contains both useful and toxic molecules

Question 48

What is reabsorption?

Answer 48

Useful substances are reabsorbed into the blood stream

Question 49

What is the collecting duct?

Answer 49

Transfers urine towards the pelvis

Question 50

What is the role of the distil convoluted tubule?

Answer 50

Adjusts the ionic composition and the Ph of blood Toxic substances are secreted into the filtrate

Question 51

Where does the loop of Henle make the tissue fluid?

Answer 51

In the medulla hypertonic

Question 52

What does the work hypertonic mean?

Answer 52

More concentrated with mineral ions

Question 53

What is the Loop of Henle also known as?

Answer 53

The formation of a salt bath

Question 54

What is the purpose of this?

Answer 54

To reabsorb water into the blood

Question 55

How does the loop of Henle reabsorb water?

Answer 55

It pumps sodium and chloride ions out of the filtrate into the surrounding tissue fluid

Question 56

Where do salt ions leave via?

Answer 56

The ascending limb

Question 57

What is special about the descending limb?

Answer 57

It is impermeable to ions (sodium and chloride) It is permeable to water

Question 58

How does water leave the descending limb?

Answer 58

It leaves by osmosis

Question 59

What happens to the water as it descends further down the loop of Henle?

Answer 59

The water or the filtrate becomes more concentrated

Question 60

In the ascending limbs what will happen to the ions?

Answer 60

The ions are actively transported out of the filtrate into the surrounding tissue

Question 61

Why does water not follow by osmosis in the ascending limb?

Answer 61

It is impermeable to water

Question 62

What will happen to the tissue fluid now that the ions have moved out and what happens to the filtrate?

Answer 62

Tissue fluid - hypertonic Filtrate - hypotonic

Question 63

Where is the filtrate most concentrated?

Answer 63

At the base of the loop

Question 64

If the filtrate is more concentrated at the base of the loop then what will this mean for the tissue fluid?

Answer 64

It is more concentrated at the base of the medulla

Question 65

What happens in the distil convoluted tube?

Answer 65

Certain substances are actively transported from the blood into the filtrate

Question 66

What is one adaptation of the distil convoluted tubule?

Answer 66

Has a brush of microvilli with numerous membrane pumps for active transport

Question 67

What is the secretion within the DCT regulated by?

Answer 67

ADH - Antidiuretic Hormone