Biology > Excretion > Flashcards

Excretion Flashcards

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1
Q

What is excretion

A

Elimination of metabolic waste from the body

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2
Q

Why do plants not need excretion

A

They make their own food and waste products of reactions are usually reused

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3
Q

Where are many waste products of plants stored

A

Vacuoles in living plants within dead cells

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4
Q

What is homeostasis

A

Maintenance of a constant internal environment in an organism

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5
Q

What are 3 example of what remain a constant internal environment

A

Temperature, fluid balance, chemical composition

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6
Q

Why is there a need to regulate temperature

A

Temperature regulates the rate of chemical reactions

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7
Q

What are the two different methods animals use to control their temperature

A

Ectothermy and endothermy

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8
Q

What are ectotherms

A

Gain or loose heat from or to their external environment

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9
Q

What are endotherms

A

Generate their own heat from metabolic reactions

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10
Q

What are the two layers of skin

A

Outer epidermis and inner dermis

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11
Q

What is beneath the dermis

A

Adipose tissue

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12
Q

Where do cells constantly divide by mitosis to produce new epidermis cells

A

Malpighian

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13
Q

What happens to cells produces in the malpighian

A

They are pushed out through the granular layer and they produce a waterproof protein called keratin

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14
Q

What happens to cells after the granular layer

A

They die due to excess keratin and lack of blood cappillaries

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15
Q

What is the name of the pigment that gives colour to skin in the malpighian layer
And what does it do

A

Melanin

Protects skin from harmful rays

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16
Q

What does the dermis consist of

A

Connective tissue and strengthening protein called collagen

Sweat glands, hair follicles, sebaceous glands, blood vessels and nerve receptors

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17
Q

What are the functions of skin

A

Epidermis protects the skin from loss of water and entry of pathogens
Dermis protects internal organs from damage
Melanin protects skin from ultraviolet rays
Sebum keeps hair moist and flexible and prevents skin from drying up

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18
Q

What vitamin is produced in skin and how

A

D

Following exposure to ultraviolet radiation and it helps calcium absorption in the intestines

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19
Q

Where is food stored in skin

A

Adipose tissue

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20
Q

What allows skin to be a sense organ

A

Variety of receptors

Eg touch pain and temperature

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21
Q

What allows skin to excrete

A

Sweat glands

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22
Q

How does skin regulate temperature in cold conditions

A

Erector muscle contracts forming goosebumps causing hair to stand up
A layer of warm air is trapped close to the skin by these hairs
Blood vessels contracts to reduce heat lost through the skin
Brain causes muscles to contract and relax causing shivering to raise temps

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23
Q

What is the term for

1) causes hair to stand up
2) causes blood vessels to contract

A

1) piloerection

2) vasoconstriction

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24
Q

How does the body react to warm conditions

A

Sweat as water evaporation lowers our body temp

Blood vessels increasing the heat loss through the skim

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25
What is the role of excretion and homeostasis
Regulates body temp Controls osmosis Controls concentration of body fluids Removes waste of metabolism
26
What are the organs of excretion
Lungs - co2 and water Skin - water and salts Kidneys - water salts urea
27
What is the urinary system consisted of
2 kidneys 2 ureters Bladder Urethra
28
What are the 3 processes in the kidneys
Filtration Reabsorption Secretion
29
What happens in filtration
Incoming blood is filtered in the outer cortex | Results in small substances being forced out of the bloodstream into the kidneys
30
What happens in reabsorption | Where does it take place
Useful materials are taken back into the blood | Occurs in cortex and medulla
31
What happens during excretion
Substances are excreted out of the cortex eg potassium | Purified blood leaves the kidneys through renal veins
32
Where does the renal vein take purified blood
Vena cava
33
What happens after filtration reabsorption and secretion
Unwanted waste and toxic products are left in the kidneys to form urine
34
What is urine composed of
96% water 2. 5% nitrogenous waste 1. 5% salt
35
Where is urea produced and how
In the liver and from excess proteins
36
Where does urine flow from and to
From medulla to renal pelvis
37
What is the bladder
Muscular organ that stores urine
38
Is the bladder under voluntary control
No
39
What muscles control urination
Sphincter
40
What are the functions of the kidneys
Excretion Osmoregulation Ph control
41
How do the kidneys control water content
Varying water content of urine eg on hot days produce low volumes of urine
42
How do the kidneys control salt content
Vary amount released in urine eg if we consume too much it will release more
43
Whwt do the kidneys do
Remove waste products of the blood
44
How does the kidneys control ph of body fluids
Producing urine that is either more or less acidic to allow ph of blood to remain at 7.4
45
What is a nephron
Functional unit of kidneys they make urine
46
What happens to the arteries when blood enters the kidneys
Blood enters kidney through renal artery Once inside kidneys this vessel divides to form renal artioles These then split to form smaller afferent arterioles These divide to form a cluster of capillaries - glomerulus Blood leaves glomerulus This then divides to form capplilaries surrounding nephron Eventually rejoin renal venules and combine and emerge from the kidneys as the renal vein
47
Where is the glomerulus found
Bowmans capsule - cup shaped structure
48
Where is urine produced
Nephron
49
What happens during filtration
Blood enters nephron in the afferent arterioles which contains waste products In the glomerulus particlas such as glucose amino acids and vitamins are forced out of the plasma and into bowmans capsule here they dialute to a solution called glomerular filtrate
50
What structure of the glomerulus helps filter
Pressure here is greater than normal blood pressure Surface area of cappilaries are large - increase area for filtration Walls of glomerular cappilaries are more porous Cells in wall of bowmans capaule are one cell thick
51
Why is pressure in the glomerulus greater
Already high pressure of the afferent arteriole is increased as efferent arterioles are narrower
52
How mucn of glomerular filtrate is reabsorbed
99%
53
Where is majority of water absorbed by osmosis
Proximal convoluted tubule
54
Where are useful molecules eg glucose reabsorbed and how
Proximal convoluted tubule | Diffusion and active transport
55
How is the proximal convoluted tubules adapted to help reabsorption
One cell thick Long Numerous infoldings High concentration of miochondria - eneegy for active transport
56
After the roximal convoluted tubule where does reabsorption tales place
Descending limb of the loop of henle
57
What is reabsorbed in the loop of henle
Small amount of water and minerals | Permeabled to water
58
What happens in the ascending limb of the loop of henle
Salts are reabsorbed as it is permeable to salts | Salts move out of nephron into fluid of the medulla
59
How is water removed out of ascending
At the top,soium is pumped out making the medulla more concentrated Water then moves out by osmosis
60
What can be reabsorbed in the distal convoluted tubules
Some water and salts | It is involved in the prcise control of water salt and ph of blood
61
What can be re absorbed in the collecting duct
Water - it is permeable to water | Also medulla is more concentrated
62
What liquid flows from collecting duct to pelvis of kidneys to bladder
Urine
63
Why does potassium need to be secreted
Too much prevents nerve impulses travelling correctly and reduced strength of muscular contractions
64
How does glomerular filtrate differ to urine
Has more water | Has more useful molecules
65
What controls the volume of urine produced
Antidiuretic hormone
66
What is ADH
Produced by hypothalamus and stored in pituitary gland Released by pituitary to blood tream Affects distal convoluted tubule and collecting ducts Causes more water to be reabsorbed in the nephron Controls osmoregulation
67
When does blood plasma become too concentrated
Drink tok much water Sweat too much or faces Consue too much salt
68
What happens when blood plasm is too concentrated
ADH released Travels to kidneys Walls of distal and collecting tubes becomes from permeable to water
69
What happens if blood plasm is too dilted
Consume too mch water Eat low salt Adh not released Distals and collecting tubes become impermeable
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