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Biology > Excretion > Flashcards

Excretion Flashcards

1
Q

What is excretion?

A

The elimination of metabolic waste produced by the body

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2
Q

What are the 3 excretory organs?

A

Lungs (CO2 and H2O vapour)
Skin (sweat (salt H2O))
Kidneys (Urine (salt, H2O and urea))

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3
Q

What is the outer layer of the skin known as?

A

Epidermis (cornified (dead) , granular (keratin), malpigphian (melanin))

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4
Q

What is the second layer of the skin called?

A

Dermis

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5
Q

What is the name of the layer of skin where fat is stored?

A

Adipose tissue

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6
Q

How does the skin function for protection?

A

Physical barrier (epidermis) against pathogens
Melanin produced in malpigphian layer protects against UV
Sebum released from sebaceous gland protects against pathogens

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7
Q

Why does the skin produce vitamin D?

A

Helps calcium in bones to be absorbed

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8
Q

How does the skin function for excretion?

A

Sweat glands produce sweat (salt and water) and is released through sweat pores.

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9
Q

How does the skin store fat?

A

Fat is located in adipose tissue and has an insulating effect.

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10
Q

How does the skin regulate temperature?

A

Cold:
Hair erector muscle contracts.
Hair follicles stand up (piloerection).
Hairs trap air insulating the body.
Blood vessels (arterioles) constrict, called vaso-constriction and lie deep holding in heat into the body. Brain causes body to shiver to generate heat.
Hot:
Hair erector muscles relax, hairs lie flat.
Blood vessels (arterioles) widen/ open called vasodilation.
Heat is lost from the body, turning red.
Sweating occurs as heat evaporates sweat causing a cooling effect

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11
Q

What is the function of the kidneys?

A

Filter blood (salt, water, urea)

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12
Q

What is the function of the renal veins?

A

Carries filtered blood away from the kidneys

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13
Q

What is the function of the renal artery?

A

Carries blood to kidney

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14
Q

What is the function of the cortex?

A

Filtration

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15
Q

What is the function of the medulla?

A

Reabsorption

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16
Q

What is the function of the ureters?

A

Carry urine from kidney to bladder

17
Q

What is the function of the bladder?

A

Stores urine (500-800 ml)

18
Q

What is the function of the urethra?

A

Carries urine away from the bladder

19
Q

What is a nephron?

A

Functional unit of a kidney

20
Q

Explain the steps involves in the supply of blood to the nephron

A
  1. Blood enters the kidney by renal artery
  2. The renal artery in the kidney splits into renal arteriole.
  3. Renal arterioles split carrying blood towards the nephron in afferent arteriole.
  4. Afferent arteriole carries blood to glomerulus which is one cell thick and located in the bowman’s capsule.
  5. Blood leaves the glomerulus and enters the efferent arteriole (which is narrower causing an increase in pressure).
  6. Efferent arteriole carries blood to capillaries, located around the nephron.
  7. Capillaries join up to form renal venule.
  8. All the renal venules join up to form renal vein carrying filtered blood away from kidney.
21
Q

What occurs at the bowman’s capsule?

A

Filtration occurs of water, salt, urea, vitamins, amino-acids, glucose.
Occurs due to
a) Increase pressure as efferent is narrower than afferent.
b) 1 cell thick for rapid diffusion.

22
Q

What occurs at the proximal convoluted tubule (PCT)?

A

Reabsorption (substances back into bloodstream)
H2O, all glucose, amino-acids, vitamins move from the nephron back into blood.
Diffusion/ active transport occurs.
Energy required so numerous mitochondria in nephron cells.

23
Q

What occurs at the descending loop of henle?

A

Reabsorption of H2O by osmosis.

24
Q

What occurs at the ascending loop of henle?

A

Permeable to salt.
Salt enters the medulla of the kidney.
Water leaves the nefron into medulla and is absorbed into the bloodstream.

25
Q

What occurs at the distal convoluted tubule?

A

Osmoregulation (precise control of H2O and salt)
H2O is secreted and reabsorbed

26
Q

What occurs at the collecting duct?

A

Permeable to water via osmosis due to salt concentration of medulla.
H2O is reabsorbed.
All collecting ducts join together to form ureters which carry urine to bladder.

27
Q

What hormone is produced in the Hypothalmus?

A

ADH (anti-diuretic hormone)

28
Q

Where is ADH released?

A

The pituitary gland

29
Q

What happens in the body when you are dehydrated?

A

Low H2O, high salt in blood
Brain detects
Pituitary gland releases ADH
Travels in blood to collecting duct to become more permeable
Water is reabsorbed into bloodstream
Salt concentration decreases in blood
Inhibits pituitary releasing ADH

Biology (9 decks)

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