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biology > ch 12 > Flashcards

ch 12 Flashcards

1
Q

define excretion

A

its a process by which the living organisms get rid of excess water, excess salts, toxins, and wastes products of metabolism

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2
Q

state and explain the function of 3 excretory organs

A

-kidneys: get rid of urine (90 % water and 10 % urea
-lungs: get rid of co2 and water
skin; get rid of sweat (excess watrer, salts and urea)

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3
Q

why do we need to preform excretion

A

to remove the excretory products from the body because they are toxic if left to accumulate

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4
Q

is urea toxic

A

yes its toxic to all body cells, esp brain cells

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5
Q

function of kidney [2]

A
  • formation of urine
    -osmoregulation
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5
Q

function of ureter

A

carry urine from kidney to urinary bladder

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5
Q

function of urinary bladder

A

stores urine

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5
Q

function of urethra

A

carry urine from bladder to outside the body

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6
Q

function of renal artery

A
  • carry oxygenated blood to kidney, blood that contains higher conc. of urea, uric acid , wastes and water
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6
Q

function of tubule

A

reabsorbtion of glucose and amino acids

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6
Q

how many nephron in each kidney

A

1 million

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6
Q

function of renal vein

A

-remove de-oxygenated blood away from kidney which contain lower conc. of urea, uric acid , wastes and water

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6
Q

what is the structural functional unit of the kidney

A

nephron

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6
Q

what is nephron

A

it is a thin, long coiled tube surronded by blood capillary all along its length

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6
Q

function of glomerelus

A

filtration of blood

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7
Q

function of capsule

A

collects the filtrate

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7
Q

function of collecting duct

A

collect urine and pass it to ureter

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8
Q

describe filtration in nephron

A

small molecules such as water, glucose and salts and urea are squeezed out of the blood into a renal capsule

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8
Q

descrive reabsorption in nephron

A

any useful substances such as glucose and water are taken back into blood

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9
Q

steps of formation of urine [6]

A
  • unclean blood coming from the aorta pass to the renal artery to the inside of kidney to the blood capillary surronding the nephron
    -large molecules cant pass through the wall of the blood capillary (act as a semi-permeable memebrane) so only small molecules pass
    -filtration occurs, which means passage of both small useful and small harmful molecules from the blood capillary to nephron
    -small useful molecules (glucose and amino acids) are reabsorbed from the nephron back to the blood capillary , this is called reabsorbption
    -small harmful molecules (urea and uric acid) are excreted along the nephron in the form of urine to ureter then urinary bladder to the outside of the body
    -cleaned blood pass back to the renal vein
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10
Q

define osmoregulation

A

keeping the amount of water in the body constant

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11
Q

what happens to water in kidney and why

A

water is filtered then excrted , bcz excess water is small harmful molecule, it should be excreted to avoid high blood pressure

12
Q

what happens to protein in kidney and why

A

neither filtered nor reabsorbed, because large molecules cant pass from the pores in blood capillary to bowman’s capsule

13
Q

what happens to glucose in kidney and why

A

filtered then reabsorbed because its small useful molecule that is needed in respiration for production of energy

14
what happens to urea in kidney and why
filtered then excreted as its small harmful molecule that is toxic to brain and body cells so should be excreted
15
function in liver [4]
-de-amination of excess amino acids (removal of nitrogen part) -regulation of blood glucose -formation of bile -storage of iron and vitamins
16
why do people eating a high protein diet have a high conc. of nitrogenous waste in their blood
because proteins are digested into amino avids which are assimilated into urea, which is a nitrogenous waste product
17
define homeostasis
keeping the internal enviroment of the body constant, in spite of changes in the external enviroment , its a trial done by the body to restore the normal condition back
18
what does homeostasis include [3]
-control of body temp -control of blood glucose -negative feedback
19
importance of control of body temp. [3]
-keep enzymes at optimum temp for maximum activity for chemical reaction -avoid denaturing of cells proteins (enzymes, hormones, cell membrane) -avoid dehydration, heat stroke
20
what organ controls body temp.
skin
21
what happens in body when the body temp increases (hot) [5]
- increases sweating -> more evaporation of water from the skin , this evaporation needs energy which is taken from the body as heat energy so the body temp falls down : face becomes wet, red and hot -vasodilation of skin blood vessels (arteriole), more blood flows to surface of the skin, so more heat lost by radiation -metabolic reactions decrease which decrease production of heat -hair erector muscle relax, which makes hair lie flat so no trapping of warm air , no skin insulation so more heat loss -no shivering
22
what happens in body when the body temp decreases (cold) [5]
- no sweating , to prevent heat loss from the body -vasoconstriction of skin blood vessels (arteriole) so less blood flows to the surface of the skin , so less heat loss by radiation -metabolic reactions increase which increase production of heat -hair erector muscle contract so makes hair upright to trap a layer of warm air next to the skin , which insulates the skin and keeps it warm -shivering to generalized contraction of all body muscles, release much heat energy to warm the body
23
role of brain (hypothalamus) in control of body temperature when body temp increases [3]
- thermoreceptors in the skin detect this rise -send nerve impulses in a sensory neuron to the hypothalamus in the brain , then the brain responds by sending nerve impulses in motor neuron to the skin effectors -skin effectors respond to decrease temp
24
how does body respond when blood glucose level increase (after a meal)
-pancreas secretes insulin hormone which decrease the blood glucose by shifting glucose from blood to liver and muscles to form glycogen
25
how does body respond when blood glucose level decrease (during fasting)
-pancreas secretes glucagon hormone which increase the blood glucose by breakdown of glycogen in liver and muscles to glucose that pass to blood
26
what hormones affect blood glucose [3]
-insulin -glucagon -adrenaline
27
what organs affect blood glucose [2]
-pancreas -liver
28
what is diabetes disease[2]
-where pancreas doesnt secrete insulin hormone -so glucose in not shifted from blood to liver, glucose accumalates in blood causing high blood glucose , glucose appears in urine ( +ve benedict test)
29
treatment of diabetes [2]
-giving patients insulin injections -avoid sugars and carbohydrates in diet
30
why is insulin not taken orally
would be digested in stomach by pepsin`
31
why does diabetes occur
damage of beta cells of pancreas which secrete insulin hormone, they are damaged by the body's immune system that attack and destroy the beta cells , occurs in young children
32
state and explain symptoms of diabetes [5]
- high blood glucose (hyper glycemia) :when the patient eats a meal rich in carbohydrates the blood glucose increases and doesnt decrease because no insulin is secreted from pancreas -glucose appears in urine (+ve benedict test) : as glucose passes to urine -patients feels thirst as they have a dry mouth so frequent drinking and frequent urination : because when glucose passes to urine it causes loss of water -increased heart rate, breathing rate and blurred vision : because when glucose passes to urine it causes loss of salts -feeling tired and cofused , may become unconcious (diabetic coma) : as no glucose enters the cells so less respiration and less production of energy
33
complications of diabetes
may lead to damage of many body organs
34
follow up for diabtes patient
checking the glucose concentration regularly
35
how is glucose concentration checked [2]
-simple sensor: measures glucose level in blood -simple dipstick: measure glucose level in urine
36
define negative feedback
it is a mechanism by which the body stops the correction after the normal conditions are restored back
37
what happens if there is no negative feedback
over-correction occurs
38
what is the normal body level for a factor called
set point
38
organs involved in homeostasis [4]
-kidney -pancreas -liver -skin
39
why does urination decrease on a hot dry day
because most of the water was lost in sweating so less water will be remaining to pass to urine
40
what does it mean if urine contains : -glucose -protein -alcohol
-glucose: patient is diabetic -protein: patient has kidney disease -alcohol : patient is alcoholic
41
what is the main component of urine
water
42
why is glucose converted to glycogen rather than kept as glucose inside the cells [2]
-glycogen is less reactive than glucose, so cannot be lost from cells by diffusion -doesnt affect the osmotic balance , no effect by osmosis

biology (19 decks)

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