Excretory System Flashcards
(101 cards)
1
Q
What is excretion?
A
The process by which the body ride itself of metabolic wastes
2
Q
What are the major contributors of the excretory system and their roles?
A
- The lungs eliminate carbon dioxide
- The large intestine eliminates toxic digestive wastes
- The liver changes toxic and products of protein metabolism into soluble compounds that the kidney can collect and eliminate
3
Q
What is the process that converts protein to carbohydrates?
A
Deamination
4
Q
How does deamination produce a carbohydrate and ammonia (a toxic gas)?
A
The removal of an amino group from amino acids
5
Q
What is produced when two molecules of toxic ammonia react with carbon dioxide?
A
Urea
6
Q
How many times less toxic is urea than ammonia?
A
About 100,000x
7
Q
What can be done with urea?
A
Can be safely transported through the bloodstream
8
Q
What are nucleus acids broken down into?
A
Uric acid
9
Q
What can excess uric acid cause?
A
Kidney stones or gout
10
Q
What are the 4 roles of the kidneys?
A
- Removal of poisonous nitrogenous wastes
- Maintenance of blood pH
- Maintenance of water balance
- Maintenance of blood pressure
- Removal of poisonous nitrogenous wastes
11
Q
What is blood carried to the kidneys from?
A
Renal arteries (branch off the aorta)
12
Q
How much blood can the kidneys hold?
A
As much as 25% of the entire blood supply
13
Q
Where are wastes taken to after being filtered by the kidneys?
A
The urinary bladder via the ureters
14
Q
What is the muscle at the base of the urinary bladder that acts as a valve?
A
The sphincter muscle
15
Q
When the sphincter muscle relaxes, where is stored urine released?
A
Through the urethra
16
Q
When the bladder is about 200mL full of urine, what happens?
A
The signal to urinate is relayed to the brain
17
Q
What are the three major structures of the kidney?
A
- The cortex
- The medulla
- The renal pelvis
18
Q
What are ureters?
A
Tubes that conduct urine from the kidneys to the bladder
19
Q
What does the renal artery do?
A
Delivers blood back to the kidney (dirty blood)
20
Q
What does the renal vein do?
A
Sends blood back to the body (clean blood)
21
Q
What are renal calyces?
A
Outer extensions of the renal pelvis that filter blood
22
Q
What is the cortex?
A
Outer layer of connective tissue
23
Q
What is the medulla?
A
Inner layer beneath the cortex, hold the major part of the nephron
24
Q
What is the renal pelvis?
A
Hollow chamber that joins the kidney with the ureter
25
What is the functional unit of the kidney?
The nephron
26
How many nephrons are there?
About one million
27
What are nephrons (generic)?
Slender tubules
28
What supplies blood to nephrons (branch from the renal artery)?
Afferent arterioles
29
What do afferent arterioles lead into?
A high pressure capillary bed; the glomerulus
30
What occurs in the glomerulus?
Filtration
31
What does blood leave the glomerulus through?
Efferent arterioles
32
Where is blood carried to from the efferent arterioles?
A capillary network (2nd set of capillaries); the peritubular capillaries
33
What do peritubular capillaries wrap around?
The kidney tubule
34
Where is blood transferred to from the peritubular capillaries?
The renal vein
35
Where is blood transferred to from the renal vein?
The venous blood system (veins)
36
What is another name for the filtrate pathway?
Urine pathway
37
What is the glomerulus surrounded by?
Bowman's capsule; a cup-like portion of the nephron
38
What does the cortex contain?
Bowman's capsule, afferent and efferent arterioles
39
Where do fluids that are to be processed into urine enter?
Bowman's capsule from the glomerulus
40
Where so fluids move after Bowman's capsule?
1. The proximal tubule (loop of henle)
2. Distal tubule
3. Collecting duct
41
What does the collecting duct do?
Collects urine from many different nephrons and merges into the renal pelvis
42
What three things does the formation of urine depend on?
1. Filtration
2. Re-absorption
3. Secretion
43
How is filtration accomplished/steps of filtration?
- Through the movement of fluid into Bowman's capsule
| - Afferent arteriole carries blood to the glomerulus (small dissolved solutes and water pass into Bowman's capsule)
44
What allows only some substances to filtered in the Bowman's capsule?
Pressure gradient (low pressure in B.c.)
45
What are too big to pass through Bowman's capsule?
Plasma proteins, RBC's, WBC's, and platelets
46
What is the "back-up" to filtration?
Re-absorption
47
What does re-absorption involve?
The transfer of essential solutes and water from the nephron back into the blood
48
Why is re-absorption so important?
Very important in maintaining the body's water balance
49
Where does re-absorption occur?
Mostly in the proximal tubule, with some in the distal tubule (minor solutes)
50
Where does most water re-absorption occur?
The descending limb of the loop of henle
51
What are most substances re-absorbed through?
Passive diffusion
52
What is actively transported out of the nephron?
Na+; sodium
53
What follow sodium by charge attraction?
Cl- and HCO3-
54
What might also diffuse out but will be re-absorbed later, creating the need for secretion?
Urea and uric acid
55
Re-absorption occurs until when?
A threshold level of a substance is reached
56
What will not be re-absorbed into the blood, instead being excreted in the urine?
Excess amounts of glucose and salts
57
When is the only time particles move back into the blood stream?
If they are low in concentration
58
When will particles stop moving back?
When threshold/equilibrium is met
59
What is the "back-up" to re-absorption (backup to the backup)?
Secretion
60
What does tubular secretion involve?
The movement of materials from the blood back into the nephron
61
How are nitrogenous wastes, histamines, excess H+, minerals, drugs, penicillin, etc. removed from the body?
By the cells in the distal tubule
62
How do cells in the distal tubule remove these substances?
Actively transport these substances back to the nephron
63
What does the distal tubule contain in order to maintain this high energy demand?
Lots of mitochondria
64
What does ADH stand for?
Anti-Diuretic Hormone
65
What does ADH do?
Helps regulate the osmotic pressure of body fluids
66
How does ADH regulate osmotic pressure?
Causes the kidneys to increase water re-absorption
67
What does the increased water re-absorption do?
Produces more concentrated urine
68
What does ADH do to the distal tubules?
Makes them more permeable to the last 15% of water that can be re-absorbed into the blood
69
How can you tell ADH has been released in your body?
Your urine is in low volume and is highly concentrated (dark yellow)
70
What detect changes in osmotic pressure of the blood?
Osmoreceptors
71
What do osmoreceptors do control?
They stimulate or inhibit the secretion of ADH
72
What response do osmoreceptors elicit?
Thirst response, inspire you to increase fluid consumption
73
Where are osmoreceptors located?
The hypothalamus in the brain
74
What substances decrease the release of ADH?
Alcohol and caffeine
75
What does the decreased release of ADH cause?
Increased urine output and dehydration
76
How do kidneys regulate blood pressure?
Regulate the amount of fluid in the blood
77
What hormone acts on the nephrons to increase sodium re-absorption from the distal tubule back into the blood?
Aldosterone
78
What will follow sodium, causing the blood volume to increase?
Chloride ions and water
79
Where is aldosterone secreted?
Adrenal cortex (just above the kidney)
80
What detects a drop in blood pressure?
The juxtaglomerular apparatus (near the glomerulus)
81
What does the juxtaglomerular apparatus do?
Causes the release of liver proteins, angiotensinogen and rennin
82
What does angiotensinogen and rennin do?
Stimulates the release of aldosterone from the adrenal gland
83
What mostly controls the pH balance?
The distal tubule
84
What is diabetes mellitus?
Caused by the inadequate production of insulin from the pancreas
85
What happens without insulin?
Blood glucose levels are extremely high and excess glucose remains in the nephron
86
What does the high osmotic gradient prevent?
Prevent water re-absorption and increases urine production
87
What are the two types of diabetes mellitus?
Type I and type II
88
What is type I diabetes mellitus?
The inability to produce insulin, degeneration of beta cells; (genetic)
89
What is type II diabetes mellitus?
Decreased insulin production or ineffective use of insulin; (lifestyle)
90
What is diabetes insipidus?
Caused by inadequate production of ADH
91
Without ADH what happens?
Urine input increases dramatically; extremely thirsty
92
What is nephritis/Bright's Disease?
Inflammation of the nephrons
93
What is a common sympton of nephritis?
Protein in the urine
94
What does the osmotic gradient have to do with nephritis?
The osmotic gradient causes an increase in urine production
95
What can nephritis lead to?
Irreversible kidney damage and eventual kidney failure
96
What are kidney stones?
Caused by the precipitation of mineral solutes from the blood
97
Where do kidney stones lodge?
In the renal pelvis or ureter, cause major pain and bleeding
98
How can kidney stones be removed?
Surgery or by using ultrasonic waves that blast the stones into smaller fragments
99
What is dialysis?
Used for patients whose kidneys no longer function properly
100
What is hemodialysis?
A machine is connected to the patient's circulatory system by a vein. Blood is pumped through a series of semi-permeable tubes submerged in solutes that remove wasted from the blood
101
What is peritoneal dialysis?
Is done through the lining of the abdominal cavity. A catheter tube is inserted and solution is fed into the abdominal cavity for two to six hours. This fluid collects waste from the body and is drained from the catheter when the process is complete
