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Grade 11 2019 > Excretion > Flashcards

Flashcards in Excretion Deck (81)
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0
Q

Example waste products of metabolisms

A
  • CO2
  • Excess water
  • Salts
  • Nitrogenous wastes (e.g. Urea, uric acid, creatinine)
  • Bile pigments
1
Q

Metabolism

A

All chemical reactions taking place in a cell

2
Q

Excretion definition

A

Removal of metabolic wastes from the body

3
Q

Egestion definition

A

Removal of undigested substances from the alimentary system

4
Q

Secretion

A

Release of useful substances produced by cells for important functions

5
Q

Where do waste products first go when they leave cells?

A
  • Diffuse from cells into tissue fluid
  • From here they are moved to the blood stream
6
Q

Excretory organs

A
  • Lungs
  • Kidneys and bladder
  • Liver and intestines
  • Skin
7
Q

Origin of CO2 as a waste

A
  • Product of cellular respiration
  • All cells in the body
8
Q

Origin of excess water as a waste

A
  • Product of cellular respiration
  • Also from intake of fluid and food
9
Q

Origin of urea as a waste

A
  • Formed largely in the liver
  • from deanimation of excess amino acids
10
Q

Origin of uric acid as a waste

A
  • End product of metabolism of nucleic acids
  • e.g. DNA and RNA
11
Q

Origin of creatinine as a waste

A

Formed from creatinine phosphate in the cells

12
Q

Origin of bile pigments as a waste

A
  • Formed in liver with haemoglobin breakdown.
  • Haemoglobin from red blood cells
13
Q

Main parts of the urinary system

A
  • Two kidneys
  • Two ureters
  • The bladder
  • The urethra
14
Q

Blood vessels associated with the kidneys

A
  • Renal artery carrying oxygenated blood and rich in wastes
  • Renal vein carrying deoxygenated blood and purified of wastes
15
Q

What is the urinary bladder

A
  • Thin walled muscular sac
  • Urine is temporarily stored here
  • Urine enters trough the two ureters
  • Exits through the urethra
16
Q

Function of the ureters

A

Transport urine from the kidneys to the bladder

17
Q

Function of the urethra

A

Transport urine from the bladder to outside the body

18
Q

Function of the sphincter muscle

A
  • Found at the base of the bladder
  • it controls the flow of urine to the urethra
19
Q

External structure of kidney

A
  • Dark bean shaped organ
  • Kidneys enclosed in fat for insulation and protection
  • Hilum - renal artery, vein and ureter enter/leave
  • Renal capsule - membrane surrounding kidney
20
Q

Internal (macro) structure of kidney - what you see when you dissect a kidney

A
  • Renal capsule (outer membrane)
  • Cortex (directly under capsule, dark red brown colour)
  • Medulla (inner region, lighter in colour)
  • Collecting tubes form pyramid (broad bases face cortex)
  • Renal papilla (inner tips of pyramids)
  • Renal calyx (renal papilla open into renal calyces)
  • Renal pelvis (calyces open into this widened region of ureter)
21
Q

Nephron

A

Structural and functional unit of kidney

22
Q

Two main parts of a nephron

A
  • Malpighian body
  • Renal tubule
23
Q

Two main parts of the Malpighian body

A
  • Bowmans capsule
  • Glomerulus
24
Q

Parts of the renal tubule

A
  • Bowman’s capsule
  • proximal convoluted tubule
  • loop of Henle
  • distal convoluted tubule
  • collecting duct
25
Q

Parts of the glomerulus

A
  • Wide afferent arteriole
  • Capillary network
  • Narrow efferent arteriole
26
Q

Parts of the loop of Henle

A
  • Descending limb
  • Ascending limb
27
Q

Parts of the nephron in the cortex

A
  • Malpighian body
  • Proximal convoluted tubule
  • Distal convoluted tubule
28
Q

Parts of the nephron in the medulla

A
  • Loop of Henle
  • Collecting duct
29
Q

Structure of the Bowman’s capsule

A
  • Inner lining of cells are specialised (called podocytes)
  • Tiny slit pores between podocytes
  • pores open into hollow capsular space
30
Q

Structure of the renal tubule

A
  • Long and twisted to increase surface area
  • Lined by cuboidal epithelial cells
  • Cells have many mitochondria for active reabsorption
  • Cells have microvilli to increase surface area
31
Q

Composition of blood plasma

A
  • Water
  • Dissolved gases
  • Dissolved useful substances (glucoce, salts, amino acids etc.)
  • Dissolved waste substances (urea, uric acid and creatinine)
  • Large plasma proteins
32
Q

Where does the efferent arteriole lead to?

A
  • A network of capillaries running closely alongside the renal tubules
  • This is called the peritubular capillary network.
  • these link up with other capillaries to join a branch of the renal vein.
33
Q

The three main processes taking place in the nephron

A
  • Glomerular filtration / ultrafiltration
  • Tubular re-absorption
  • Tubular excretion
34
Q

Glomerular filtration

A
  • Blood in glomerulus under great pressure (narrower efferent arteriole)
  • small substances forced out through pores into capsular space
  • i.e. Water, glucose, amino acids, glycerol, fatty acids, salts as well as waste products urea, uric acid and creatinine
  • blood cells and plasma proteins stay behind in blood vessels
  • this filtrate called glomerular filtrate
  • process is not selective, contains waste and useful substances.
35
Q

Tubular re-absorption

A
  • As glomerular filtrate passes proximal convoluted tubule
  • water reabsorbed by osmosis into peritubular capillaries
  • other useful substances re-absorbed actively
  • cuboidal cells of the tubule have mitochondria for active transport and microvilli to increase surface area.
  • filtrate with useful substances removed is now called dilute urine
36
Q

Tubular excretion

A
  • Wastes actively transported from the blood into the renal tubule
  • e.g. Creatinine, drugs, ammonia, potassium, hydrogen and bicarbonate ions
37
Q

How water is conserved (tubular reabsorption process)

A
  • Sodium and chlorine ions pumped out of loop of Henle
  • dilute urine leaving the loop of Henlee has a very high water potential
  • because of a steep concentration gradient, water leaves the distal convoluted tubule by osmosis
  • depending on the water levels of the body, urine is either more dilute or concentrated
38
Q

Hormone that regulates how much water is reabsorbed

A

Anti-diuretic hormone (ADH)

39
Q

The action of ADH on the distal convoluted tubules and collecting ducts

A
  • It’s presence reduces the permeability of the distal convoluted tubules and collecting ducts
  • this reduces water reabsorption
  • urine is more diluted
40
Q

Kidney tubule response if blood becomes too alkaline

A
  • Hydrogen ions concentration in blood is too low (high pH)
  • cells of tubules remove more bicarbonate ions
  • Various ions act as buffer in filtrate (resists pH change)
  • pH in blood returns to normal
41
Q

Homeostasis

A
  • a process that keeps the amounts of substances and conditions of the body within narrow limits.
  • maintained by constantly adjusting these to prevent any large changes.
42
Q

Homeostasis of water

A

Osmoregulation

43
Q

Osmoregulation process (shortage of water in body)

A
  • osmoreceptors in hypothalamus stimulated
  • pituitary stimulated to produce more ADH
  • ADH via blood increases permeability of distal convoluted tubules
  • more water passes from tubules into blood by osmosis
  • less water remains in tubules
  • concentrated urine is excreted
44
Q

Osmoregulation process (excess of water in body)

A
  • osmoreceptors in hypothalamus stimulated
  • pituitary stimulated to produce less ADH
  • less ADH decreases permeability of distal convoluted tubules
  • less water passes from tubules into blood by osmosis
  • more water remains in tubules
  • dilute urine is excreted
45
Q

What is aldosterone

A
  • A hormone
  • regulates the salt concentration of the blood and tissue fluid
  • secreted from the cortex of adrenal glands
46
Q

Homeostasis of salt balance (e.g. when sodium in the body is too low)

A
  • Sodium levels on the blood drop
  • More aldosterone secreted from the adrenal glands
  • The renal tubules are stimulated to increase active reabsorption of sodium ions from the filtrate into the blood
  • Sodium levels in the blood increase
48
Q

Causes of kidney failure

A
  • Overuse of painkillers
  • Chronic high blood pressure
  • Type 2 diabetes
  • Injury
  • Infection e.g. Bilharzia
49
Q

Kidney dialysis

A
  • A short term treatment for those with kidney failure
  • Entire blood volume is passed through a series of filters
  • cleaned blood is returned to the body
  • Done mainly in hospital with a dialysis machine
  • several times per week
  • expensive
50
Q

Long term solution for kidney failure

A
  • Kidney transplant
  • Dysfunctional kidney removed
  • Replaced by a healthy donated kidney
51
Q

Process of dialysis

A
  • Blood is removed from an artery
  • A substance is added to prevent the blood from clotting
  • It is pumped into semi-permeable tubes in the dialysis machine
  • On the other side of these tubes is dialysis fluid
  • This contains water, glucose and salts of same concentration as the blood
  • Waste molecules move through the membrane into the dialysis fluid by diffusion
  • useful molecules don’t move through (no concentration gradient)
  • cleaned blood returned to a vein of the person
52
Q

Issues with kidney transplants

A
  • Risk of rejection (immune system attacks foreign cells)
  • Finding a donor hard - often a close relative required
  • shortage of donors
  • Immuno-suppressants required for life
  • Expensive
  • public health system in SA will not treat those over 50 years old due to its cost
53
Q

Kidney stone

A
  • A solid formed from minerals in the diet
  • E.g. Calcium, uric acid
54
Q

Increased risk for getting kidney stones

A
  • Dehydration
  • Excess animal protein
  • Sodium (salt)
  • Sucrose
  • Fructose
  • High fructose corn syrup (e.g. In Coke)
55
Q

Getting rid of kidney stones

A
  • Small ones pass with urination
  • Larger ones need treatment as they can cause blockages
  • ultrasound to shatter them
  • surgery
56
Q

Effect and symptoms of kidney stones

A
  • Blockage of different parts of the renal system
  • Renal colic - intense pain
  • Sometimes nausea and vomiting
57
Q

Kidney failure caused by medicines

A
  • Analgesic nephropathy
  • Irreversible damage
  • Damage builds up through time
  • Leads to kidney failure
58
Q

Common medicines causing kidney damage

A
  • Paracetamol (e.g. Panado)
  • Ibuprofen (e.g. Neurofen)
59
Q

Risk of damage to kidneys by medicines increases…

A
  • With dehydration
  • With large amounts of exercise (e.g. long distance runners) mainly due to dehydration
60
Q

An example parasite that affects the urinary system

A

Schistosomiasis / bilharzia

61
Q

Symptoms of bilharzia

A
  • Painful urination
  • Blood in urine
62
Q

Portal of entry for Bilharzia

A
  • Schistosomiasis flatworms
  • Burrow into skin from infected waters
  • Female lays eggs in blood vessels lining the bladder
63
Q

Place of exit by bilharzia from humans

A
  • Eggs have spike that cuts blood vessel
  • They enter bladder
  • Exit body with next urination
64
Q

Secondary host of bilharzia

A

A snail

65
Q

Complications from bilharzia infection

A
  • Eggs or larvae can obstruct different part of the system
  • If not treated, can lead to chronic kidney failure
66
Q
A

Ureters

67
Q
A

Urinary bladder

68
Q
A

Urethra

69
Q
A

Renal pelvis

70
Q
A

Adrenal glands

71
Q
A

Renal capsule

72
Q
A

Renal cortex

73
Q
A

Renal pyramids

74
Q
A

Renal calyces

75
Q
A

Renal pelvis

76
Q
A

Renal artery

77
Q
A

Renal vein

78
Q
A

Renal medulla

79
Q
A

A: Collecting duct

B: Malpighian body

80
Q
A
  • A nephron
  • Structural and functional unit of the kidney
81
Q
A

A: Afferent arteriole

B: Bowmans capsule

C: Glomerulus (capillaries)

D: Distal convoluted tubule

E: Collecting duct

F: Loop of Henle

G: Proximal convoluted tubule