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study cards > Bio U4 Excretion > Flashcards

Bio U4 Excretion Flashcards

1
Q

What are the effects of excess CO2

A

Excess CO2 is toxic

Reduces oxygen transport
Produces CARBAMINOHAEMOGLOBIN
Respiratory Acidosis

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2
Q

Function of the gallbladder

A

Stores BILE made by the liver

Bile emulsifies fats

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3
Q

Hepatocytes

A

Carry out hundreds of metabolic processes and the liver has a important role in homeostasis

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4
Q

Hepatic artery

A

Carries oxygenated blood from the heart

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5
Q

Hypatia portal vein

A

Carries deoxygenated blood from the digestive system

Carries blood away from the liver

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6
Q

What are hepatocytes

A

Liver cells
👀remove some molecules from the blood and pass other molecules into the blood
👀contain many mitochondria needed for a large supply of ATP
👀contain many ribosomes for protein synthesis

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7
Q

Sinusoids

A

Where oxygenated blood from the HEPATIC ARTERY and deoxygenated blood from the HEPATIC PORTAL VEIN are mixed

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8
Q

Kupffer cells

A

Specialised macrophages involved in the breakdown and RECYCLING of old red blood cells.
One product of haemoglobin is the breakdown of bilirubin which gives faeces it’s brown colour

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9
Q

Break down of proteins

A

Amino acid->ammonia keto acid->urea

(Deammination) (Ornithine cycle)

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10
Q

Deamination

A

Amino acid+O2->ketoacid+ammonia

Ammonia is very toxic and very soluble

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11
Q

Ornithine cycle

A

NH3 + CO2 —>CO(NH2)2 + H2O

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12
Q

The liver has…

A

Many enzymes that render toxic molecules less toxic

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13
Q

Catalase

A

Converts hydrogen peroxide to oxygen and water

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14
Q

Ethanol dehydrogenase

A

Breaks down ethanol to Ethanal

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15
Q

Outline detoxification

A

Ethanol->EthAnAl->ethanoic acid->ACETYL COENZYME A

ACETYL coenzyme A is non toxic and is used in respiration

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16
Q

What are the components of the nephron

A 
Glomerular Capillary 
PCT- proximal convoluted tubule 
Renal bowman's capsule 
Loop if Henle
Descending Limb
Ascending limb 
DCT- distal convoluted tubule 
collecting duct (releases urine)
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17
Q

Renal bowman’s capsule

A

Cup shaped structure that surround the glomerulus

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18
Q

Proximal convoluted tubule

A

Site of SELECTIVE REABSORPTION where certain substrates are reabsorbed

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19
Q

Loop of Henle

A

Loop that creates a counter current flow, and makes salt transfer between limbs more efficient

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20
Q

Distal convoluted tubule

A

Where SOME water is reabsorbed into the blood

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21
Q

Collecting duct

A

Site if A LOT of water reabsorption

22
Q

Afferent Arteriole

A

Brings blood to the glomerulus

23
Q

Glomerulus

A

Capillary network and site of ultrafiltration

24
Q

Efferent Arteriole

A

carries AWAY from the glomerulus

25
Q

Peritubular

A

Surround the nephron

Some substances move from the filtrate back into the blood

26
Q

Define Ultrafiltration

A

Filtration at the molecular level in the glomerulus of the kidneys

27
Q

Outline ultrafiltration

A

The Afferent Arteriole has a WIDER DIAMETER than the Efferent Arteriole

This difference in diameter creates a high HYDROSTATIC pressure in the glomerulus

The high hydrostatic pressure forces some substances out of the blood. The pass through the PORES in the CAPILLARY across the BASEMENT MEMBRANE and through the PODOCYTES

PODOCYTES have major processes which INCREASE surface area
⚡️proteins and red blood cells are too big to pass through
⚡️water, amino acids, glucose, urea, and ions can pass through

28
Q

Outline selective reabsorption

A

Na+ is actively transported into the blood from the cells lining the PCT

This lowers the concentration of Na+ inside these cells

As a result Na+ moves from the filtrate into the cells through co-transporter proteins and brings glucose or a amino acid into the cell
These are transported into the blood

29
Q

Outline water reabsorption

A

Na+ and Cl- are actively transported out of the ascending limb

This lowers the water potential of the blood surrounding the nephron and causes water to move out of the descending limb into the blood by osmosis. Water is unable to leave the ascending limb because it is impermeable to water

This creates a very negative water potential in the base of the loop of Henle

As a result, little Na+ and Cl- move out of the ascending limb by diffusion

When the filtrate reaches then DCT the water potential is very high due to so much Na+ and Cl- being pumped out of the ascending limb

Water is drawn out of the DCT and collecting duct depending on the level of ADH in the blood

30
Q

Selective reabsorption

- where does most reabsorption occur

A

85% of filtrate is reabsorbed in the PCT

cells lining the PCT are specialised to achieve this reabsorption

31
Q

Outline The Hypothalamus and Posterior Pituitary

A

💭ADH is manufactured in the cell body of the neurosecretory cells. ADH flows down the axon to the terminal bulb in the posterior pituitary gland. Stored here until needed.

💭water potential of the blood is monitored by osmoreceptors in the hypothalamus of the brain. These cells respond to the effect of osmosis. When water potential of the blood is very low the osmoreceptors lose water by osmosis. This causes them to shrink and stimulate the neurosecretory cells in the hypothalamus.

💭when the neurosecretory cells are stimulated they send action potentials down their axons and cause the release of ADH

32
Q

The effect of ADH on the collecting duct wall

A

ADH is detected by the cell receptors

Enzyme controlled reactions

Vesicles containing water permeable channels(aquaporins) fuse to the membrane

More water is reabsorbed

33
Q

Osmoregulation

A

The control of water levels and salt levels in the body

34
Q

Antidiuretic hormone

ADH

A

Released from the pituitary gland and acts on the collecting ducts in the kidneys to increase their reabsorption of water

35
Q

Osmoreceptors

A

Receptor cells that monitor the water potential of the blood

If the blood has a low water potential, water is moved out of the osmoreceptors cells by osmosis, causing them to shrink

This causes stimulation of neurosecretory cells

36
Q

Hypothalamus

A

part of the brain that contains neurosecretory cells and various receptors that monitor the blood

37
Q

Neurosecretory cells

A

Are specialised cells that act like nerve cells but release hormones into the blood

ADH is manufactured in the cell body and passes down the axon to be stored in the terminal bulb

If an action potential passes down the axon then ADH is released from the terminal bulb

38
Q

Posterior pituitary gland

A

Releases ADH

39
Q

Fall in water potential

A

If the water content of the blood drops, the water potential drops

This is detected by the osmoreceptors in the hypothalamus

The POSTERIOR PITUITARY GLAND is stimulated to release MORE ADH into the blood

More ADH means the collecting duct walls are more PERMEABLE so more water is reabsorbed I to the blood by osmosis

Small amount of highly concentrated urine is produced and less water is lost

40
Q

Rise is water potential

A

Water content rises so the water potential rises

Detected by the osmoreceptors in the hypothalamus

POSTERIOR PITUITARY GLAND releases LESS ADH into the blood

Less ADH means the collecting duct walls become less permeable so less water is reabsorbed into the blood by osmosis

Large amount of dilute urine is produced and more water is lost

41
Q

What are some reasons for kidney failure

A

Diabetes mellitus
Hypertension
Infection

42
Q

What happens when kidneys fail completely

A

Body fills with extra water and waste products

Hands and feet swell

Patients feel tired and weak because body needs clean blood to work effectively

If not treated could lead to death

43
Q

What are benefits of the kidneys

A

They keep your blood composition constant

Filter blood to remove excess water and waste products

1/4 of your blood supply passes through your kidneys each minute

44
Q

Dialysis

A

Any substances in excess in the blood diffuse across the membrane and into the dialysis fluid (through artery)

Any substances that are low in concentration diffuse into the blood from the dialysis fluid through diffusion

An ANTICOAGULANT is added to the blood to prevent it from clotting

a patient needs 3-4 dialysis sessions per week and last 4-5 hours each

Blood and dialysis fluid move in opposite directions in a counter current flow to maintain a steep concentration gradient

45
Q

Treatment of kidney failure through Transplant

A

The transfer of a healthy kidney from one person into the body of the patient

Best chance of success is when the healthy kidney is taken from a LIVING RELATIVE as this reduces the chance of rejection.

The body would recognise the new kidney as FOREIGN and eventually reject it

46
Q

What are the advantages of a kidney transplant

A

1⃣Freedom from time consuming dialysis

2⃣less limited diet

3⃣feeling better physically

4⃣better quality of life

5⃣no longer seeing oneself as chronically ill

47
Q

What are the disadvantages of kidney transplant

A

Need IMMUNE-SUPPRESSANTS for the life of the kidney

Need major surgery under a general anaesthetic

Risks of surgery include; infection, bleeding, and surround organ damage

Frequent checks for signs of infections

There are side effects - anti-rejection medicine causes fluid retention and high BP

Immune suppressants incense susceptibility to infection

48
Q

Outline pregnancy testing

A

Test for hormone hCG (human chorionic gonadotropin) is secreted by growing embryo

hCG binds to the antibodies on the beads of the pregnancy strip

The urine moves up the test strip carrying the beads with it

If there is hCG present the strip would turn blue because the immobilised antibodies bind to the hCG, concentrating the blue beads in the area

49
Q

Anabolic steroids

A

Anabolic steroids increase protein synthesis within cells resulting in the build up if muscle tissue

They have dangerous effects like liver damage

50
Q

What is a test for testing for anabolic steroids and how is it carried out

A

GAS CHROMATOGRAPHY

urine sample is vaporised and passed through a column surrounded by cool liquid

Different substances move through the column at different rates

The length of time taken for the substances in the sample to pass through the column is compared to the time taken for a STEROID to pass through the column

51
Q

define excretion

A

The removal of METABOLIC waste from the body

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