5.2 EXCRETION Flashcards
(63 cards)
1
Q
Define excretion
A
- the removal of metabolic waste from the body
2
Q
State the three types of toxic metabolic waste
A
- Carbon dioxide
- Nitrogenous compounds
- Bile pigment
3
Q
What are liver cells called?
A
- Hepatocytes
4
Q
Draw the external and internal structure of the liver
A
5
Q
What does the hepatic artery in the liver do?
A
- Supply’s the liver with oxygenated blood from the heart
6
Q
What does the hepatic vein in the liver do?
A
- Take away deoxygenated blood from liver to the heart
7
Q
What does the hepatic portal vein in the liver do?
A
- Supply nutrient filled deoxygenated blood to the liver from the digestive system
8
Q
Describe the contents of the bile duct in the liver
A
- Contains bile which contains the bile pigment called bilirubin
9
Q
State the two roles of kupffer cells
A
- Act as macrophages to engulf foreign matter
- Break down and recycle old red blood cells into bilirubin which is excreted in faeces
10
Q
State the type of cell that produces bile
A
- Hepatocytes
11
Q
State two adaptations of hepatocytes
A
- Dense cytoplasm
- Many mitochondria
12
Q
State the functions of the liver
A
1) Storage of glucose
2) Detoxification
3) Urea formation
13
Q
Describe the process of storage of glucose in the liver
A
- In response to insulin the hepatocytes start to absorb excess glucose and convert it into glycogen where its stored
14
Q
Define detoxification
A
- the breakdown of unwanted chemicals like drugs, alcohol, hormones and toxins
15
Q
Draw the process of detoxification of alcohol in the liver
A
16
Q
State what acetyl coenzyme A is used for
A
- Respiration
17
Q
State the two steps of urea formation in the liver
A
1) Deamination
2) Ornothine cycle
18
Q
Describe the two steps of urea formation in the liver
A
- Deamination forms ammonia and keto acid from an amino acid and oxygen
- Ornothine cycle forms urea and water from ammonia and carbon dioxide
19
Q
Draw the external structure of the kidneys
A
20
Q
State the role of the renal artery and renal vein in the kidneys
A
- Renal artery provides oxygenated blood
- Renal vein takes away deoxygenated blood
21
Q
Draw the structure of a nephron in the kidneys
A
22
Q
State the three functions of the kidneys
A
- Ultrafiltration
- Selective re-absorbtion
- Formation of urine
23
Q
State where ultrafiltration occurs in the nephron
A
- Bowmans capsule
24
Q
State where selective re-absorbtion occurs in the nephron
A
- Proximal convoluted tubule
25
State where formation of **urine** occurs in the **nephron**
- **Collecting duct**
26
State why the **afferent arteriole** is wider than the **efferent arteriole**
- The create a **hydrostatic pressure gradient** between the **glomerulus** and **bowmans capsule** so **ultrafiltration** happens
27
State the **three** layers of **filter** substances must go between the **glomerulus** and **bowmans capsule**
- **Capillary endothelium** (has gaps)
- **Basement membrane**
- **Bowmans capsule podocyte epithelial cells** (hair like projections)
28
State the **five** things that are **filtered** out the **glomerulus** during **ultrafiltration**
- **Water**
- **Amino acids**
- **Mineral ions**
- **Glucose**
- **Urea**
29
State the **two** things than remain in the **capillaries** during **ultrafiltration**
- **Proteins**
- **Erythrocytes**
30
Describe the process of **selective re-absorbtion** in the **kidneys**
1) **Sodium ions** are **actively** pumped **out** of cells lining the tubule and into the **blood plasma**
2) **Concentration** of **sodium ions** in **cytoplasm decreases**, forming a concentration **gradient**
3) **Sodium ions** diffuse into cells lining the tubule via **co-transporter proteins** so carry a **glucose** or **amino acid** with them
4) **Glucose** and **amino acids** diffuse from cell lining tubule into the **blood plasma**
31
State **four** ways the cells **lining** the **proximal convoluted tubule** is specialised for **selective re-absorbtion**
1) **Highly folded plasma cell surface membranes** to increase **surface area** for **absorbtion**
2) Plasma cell surface membrane contains **cotransport proteins**
3)
32
State where **water** is **reabsorbed** in the **nephron**
- **Loop of henlee**
33
Draw a diagram of **water reabsorbtion** at the **loop of henlee**
34
Define **osmoregulation**
- The **control** of **water potential** in the body
35
State the usefulness of **osmoregulation**
- So **excess water** doesn’t enter cells and cause **lysis**
- So **excess water** doesn’t leave cells
36
Describe the **urine** produced by **kidneys** when **water** is **abundant** in the body
- **Large volumes**
- **Dilute urine**
37
Describe the **urine** produced by **kidneys** when **water** is **absent** in the body
- **Low volumes**
- **Concentrated**
38
Describe the state of the **collecting ducts** when **water** is **abundant** in the body
- Collecting duct **walls** become **less permeable** so that **less water** is **reabsorbed** into the **bloodstream** as is not needed
- **Higher volume** of **urine** produced
39
Describe the state of the **collecting ducts** when **water** is **absent** in the body
- Collecting duct **walls** become **more permeable** so that **more water** is **reabsorbed** into the **bloodstream** as it’s needed
- **Lower volume** of **urine** produced
40
State the role of **ADH**
- Controls the **permeability** of the **collecting duct**
- When released into the **bloodstream**, the **collecting duct walls** become **more** **permeable** so **more water** is **re-absorbed** back into the **blood**
41
Describe the response to **ADH** release into the **bloodstream**
- **ADH** binds to **specific receptors** of **cells** of **collecting wall duct**
- Cause a chain of **enzyme-controlled** reactions
- Results in **vessels** containing **aquaporins** to **fuse** with the **plasma membrane**
- **More water** is **reabsorbed** into the **blood**
- **Less volume urine** with a **low water potential** produced (more **solute concentrated**)
42
Describe the response to **ADH** NOT release into the **bloodstream**
1) There is **low ADH** so the **plasma cell surface membrane** begins to **fold inwards** in order to **remove** the **aquaporins** from the **membrane**
2) This **reduces** the **permeability** of the **collecting duct walls**
3) **Less water** is **reabsorbed** into the **blood**
4) **More water** passes down the **collecting duct**
5) **Higher volume** with a **high water potential urine** produced
43
Define **osmo-receptor**
- A **sensory receptor** in the **hypothalamus** that detects changes in **water potential**
44
Explain how **osmo-receptors** control **water potential** in terms of **negative feedback**
1) When **water potential** is **low** (**negative**) the **osmo-receptor cells** loose water by osmosis and **shrink** as a result
2) Therefore **ADH** is **released** into the **bloodstream** to make **collecting duct walls more permeable**
3) Thus, **wtaer potenial increases** back to the **norm/optimum**
45
Define **kidney failure**
- When the kidneys **cannot osmoregulate** or filter **waste products** (**urea**) out of the **blood**
46
State the **two** ways of assesing **kidney failure**
1) **Glomerular filtration rate** (**GFR**)
2) **Analysing** **urea** for **proteins**
47
Define and explain **glomerular filtration rate** (**GFR**)
- The **rate** at which **fluid** enters the **nephrons** (per **minute**)
- Normal range is between 90-120 cm³ min⁻¹
48
Explain what having **proteins** in the **urine** indicates
- Indicates that **filtration mechanism** is **damaged**
- (**Kidney failure**)
49
State **four** causes of **kidney failure**
1) **Diabetes** (**T1** and **T2**)
2) **Heart disease**
3) **Hypertension**
4) **Infection**
50
Define **renal dialysis**
- Machine used to **artificially regulate concentrations** of **solutes** in the **blood**
51
State the **two treatments** for **kidney failure**
1) **Renal dialysis**
2) **Kidney transplant**
52
State the **two** types of **renal dialysis**
1) **Haemodialysis**
2) **Peritoneal dialysis**
53
Explain how **renal dialysis** works to **regulate solute concentrations**
1) **Waste products**, **excess fluids** and **mineral ions** are moved out the **blood** by passing it over a **partially permeable dialysis machine** that allows **exchange** of **substances** between **blood** and **dialysis fluid**
2) The **dialysis fluid** contains the **correct concentrations** of **substances** found in the **blood plasma**
3) Any substance **in excess** in the **blood** **diffuses** across the **membrane** into the **dialysis fluid**
4) Any substance in **low concentrations** diffuse from the **dialysis machine** into the **blood**
54
Explain **haemodialysis**
- Blood for **artery** or **vein** is passed into an **artifical dialysis membrane** shaped to form **many artificial capillaries** which **increases surface area** for **exchange**
- **Heparin** is added to prevent **clotting**
- **Artificial capillaries** are surrounded by **dialysis fluid** which flows in a **countercurrent direction** to improve **efficiency** of **exchange**
55
Explain **peritoneal dialysis**
- The **dialysis membrane** is the persons **own abdominal membrane** (**living cells**)
- The **dialysis fluid** is inserted directly into the **gaps** between the **abdominal walls** and **organs**
- **Dialysis fluid** is **drained afterwards**
- (Requires a **healthy diet**)
56
Define **immunosuppressant drug**
- **Prevents** the **immune system** from recognising a **new organ** as **foreign**, so the body **doesnt reject** it
57
State **four** advantages of a **kidney transplant**
1) Doesnt require **repeated dialysis**
2) Their **diet** is **less limited**
3) Better **quality** of **life**
4) No longer **chronically ill**
58
State **three** disadvantages of a **kidney transplant**
1) Require longterm **immunosuppressent drugs**
2) Risk of **rejection**/**surgery**
3) **Difficulty** finding a **donor**
59
Describe **urine testing**
- Tests for **small molecules** in the **urine** not **reabsorbed** into the **nephron**
60
State and describe **five** uses of **urine testing**
1) **Glucose** for the diagnosis of **diabetes**
2) **Alcohol** to determine **blood alcohol levels**
3) **Recreational drugs**
4) **hCG** in **pregnancy testing**
5) **Anabolic steroids**
61
State why **monoclonal antibodies** are used in **pregnancy testing**
- Because they are **specific** to **one complementary molecule**
62
Describe the steps of **pregnancy testing**
1) **Urine** in poured onto the **stick**
2) **hCG binds** to **mobile antibodies** that are attached to a **blue head**
3) **Mobile antibodies** move down the test stick
4) If **hCG** is present, it **binds** to the **fixed antibodies** and forms a **blue line**
5) **Mobile antibodies** with **no hCG** attached **bind** to another **fixed site** to prove the **test** is **working**
63
State why **hCG** is able to be **detected** in the **urine**
- It has a **molar mass** of **less** than **69,000**
