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AP Biology > Grade 12: Homeostatis: Unit 6 : FULL UNIT REVIEW > Flashcards

Grade 12: Homeostatis: Unit 6 : FULL UNIT REVIEW Flashcards

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1
Q

What is homeostasis? What does it maintain?

A

A constant physiological adjustment of the body in response to external environment changes
Although the world varies around us over time, our bodies maintain a stable internal environment!
37° C, 0.1% blood glucose and a blood pH of 7.35!

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2
Q

What happens when you exercise?

A

1- body temperature increases
2- O2 levels are used up
3- increased cellular metabolism
4- evaporation of sweat to cool off
5- heat rate increases to increase blood flow (to get O2 levels back up)
6- pancreas signals breaking down of bio molecules to get energy needed to exercise

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3
Q

Homeostatic control system

A

1 - receptors or sensors — organs that detect changes or sense when conditions are not within the normal range
2 - control centre or integrator — organs which process information or receives from the receptor and sends signals to another part of the body

  1. Effector — coordinating centre sends signals to an organ / tissue which will normalize original organ
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4
Q

Coordination of Body Functions

A

The activity of various specialized parts of an animal are coordinated but the two major systems of internal communication

The nervous system — involved with high- speed messages
The endocrine system — involved in the production, release and movement of chemical messengers

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5
Q

Chemical signs?

A

Hormones = produced by the endocrine system convey information between organs of the body
Pheromones = chemical signals used to communicate between different individuals
Neurotransmitters = chemical signals between cells on a localized scale (over short distances; between neurons)

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6
Q

Feedback systems (negative)

A

Buildup of the end product of the system shuts the system off
The response counteracts further change in the same direction

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7
Q

Negative feedback process

A

—> decreases an action
—> stops when return to normal
—> most homeostatic control mechanisms are negative feedback

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8
Q

Feedback systems (positive)

A

A change in some variable that triggers mechanisms that amplify the change

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9
Q

Positive feedback steps

A

—> increase an action
—> must be turned off by outside event
—> decrease an action
—> could run away = death

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10
Q

What is thermoregulation?

A

The process in which animals maintain an internal temperature within a tolerable range
It is critical to survival because biochemical and physiological processes are sensitive to changes in temperature
—> enzymatic reactions
—> properties of membranes

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11
Q

One of two ways to maintain BT?

A

Poikilothermy: body temperatures is not controlled but varies with ambient temperature, as in invertebrates and most fishes. Poikilotherms do not necessarily have widely fluctuating body temperatures

Homeothermy: maintenance of constant body temperature that is usually high! Here consistency matters over heat!

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12
Q

Modes of heat exchange? —> explain

A

Radiation
Evaporation
Convention
Conduction

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13
Q

Balancing heat loss and gain

A

1- insulation
2- circulatory adaptations
3- cooling by evaporative heat loss
4- adjusting metabolic heat production

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14
Q

Insulation

A

feathers, hair or fat layers
Reduces the flow of heat between an animal and its environment
Lowers energy cost of staying warm
Most land animals and birds react to cold by raising fur or feathers
—> traps a thicker layer of fur
—> increasing its insulating power

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15
Q

Goosebumps?

A

Raise hair on body
Inherited by ancestors
We rely on a layer of fat underneath the skin

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16
Q

Circulatory adaptations

A

We can alter the amount of blood (hence heat) flowing between the body core and skin
Vasodilation
Muscles in superficial blood vessels relax
Increases the diameter of vessels = more blood
Increases heat transfer, releasing heat energy to surroundings
Vasoconstriction
Muscles in superficial blood vessels contract
Smaller diameter of blood vessels = less blood
Reduces heat transfer: preventing heat loss
Keeps blood (and heat) in interior of body where it’s needed

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17
Q

Evaporative heat loss

A

When environmental temperatures are above body temperature animals
Sweat, pant, bathe, spread saliva over body surfaces
Heat is carried away with water molecules as they change into a gas

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18
Q

Adjusting metabolic heat production

A

Shivering and moving —> heat production is increased by muscle activity
Non shivering thermogenesis (NGT) certain hormones can cause mitochondria to increase their metabolic activity and produce heat instead of ATP

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19
Q

What is the insulating material for mammals

A

The integumentary system (hair,skin,nails)

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20
Q

What regulates our temperature

A

Hypothalamus: contains a group of nerve cells that function as a thermostat

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21
Q

What is the endocrine system? What do the glands do?

A

Endocrine glands secrete hormones into the bloodstream

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22
Q

What are hormones

A

Chemical messages release in one part of the body, travel through bloodstream and affect the activities of target cells in other parts of the body

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23
Q

Example of nervous x endocrine system

A

Endocrine system is much slower than the nervous system, but they work together
Nervous system: reaction to a hot stove
Endocrine: growth rate as a teenager

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24
Q

Endocrine hormones

A

We have over 200 hormones or hormone like chemicals within the body
They can
Regulate growth and development
Change metabolism
Blood sugar
Blood pressure
Immune response

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25
Q

Gigantism

A

When too much growth hormones (GH) are released in early childhood

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26
Q

Pituitary dwarfism

A

Too few growth hormones produced

27
Q

Regulation of hormones

A

The hypothalamus receives signals from various sensors in the body and releases “releasing hormones” these stimulates the pituitary gland

28
Q

Tropic hormones

A

Hormones that stimulate endocrine glands to release other hormones are called tropic hormones. Most released from hypothalamus and pituitary glands are tropic hormones

29
Q

2 types of hormones

A

Steroid hormones: fat soluble molecules made from cholesterol : cortisol
Protein hormones: water soluble, molecules derived from amino acids or chains of amino acids

30
Q

Steroid hormones

A

Lipids and hydrophobic, meaning they can easily interact with cell membranes that consist of phospholipids
Therefore when a steroid hormone travels through the blood and encounters a cell, it does not stop at an cell membrane to get in. It simply can shoot through!

31
Q

Protein hormones

A

A hydrophilic hormone cannot get into a cell, it can only bind to a receptor located on the outside of its target cells membrane
But the hormone is brining a message from your body to that target cell
Because the hormone tells the target cell that it needs to carry our some function for the body it is refereed to as the first messenger

32
Q

Second messenger?

A

Within a target cell and must continue to carry the message of the hormone within the cell to get the job done
—> known as cAMP

33
Q

What is osmosis

A

Osmosis is the selective passageway of solvent molecules through a porous membrane, from a diluted solution to a more concentrated one

34
Q

What is osmosis pressure

A

The amount of pressure required to stop osmosis

35
Q

Osmosis Types

A

Isoosmotic (Isotonic): Solutions have
an equal concentration of solute and so
equal osmotic pressure.

 Hyperosmotic (Hypertonic): Solution
with higher concentration of solute.

 Hypoosmotic (Hypotonic): Solution
with lower concentration of solute.

36
Q

Osmoregulation

A

The maintenance of osmotic pressure in the fluids of an organism, by the control of water
In unicellular organisms, waste can move directly out of a cell
Excess water is regulated by contractile vacuums which pump out excess water
In multi-cellular organisms, excess cells and structures are required to help in the removal of waste

37
Q

Why is the removal of waste products important? List some main parts of the body and their functions in this.

A

Lungs -> CO2
Large Intestine -> toxic wastes
Liver -> transforms toxins such as alcohol or heavy metals into soluble materials
Transforms products of protein metabolism into metabolites
Kidneys -> Remove waste, regulate Blood pH and maintain Water Balance

38
Q

What is Deamination

A

the breaking up of amino acids. Produces ammonia (NH3) which is toxic
and must be further processed

39
Q

What is Urea?

A

is a combination of 2 molecules of
highly insoluble, toxic ammonia (NH3) mixed
with 1 molecule of CO2 which is a soluble
compound

40
Q

What is Uric Acid?

A

waste product formed from the
breakdown of nucleic acids

41
Q

What does the liver do in excretion?

A

responsible for removing/breaking
down waste in the blood which is then sent to
the kidneys to be filtered into the bladder

42
Q

Why does urine differ in color?

A

The amount of water present within the urine

43
Q

What does clear urine indicate

A

Good hydration, Overhydration, Mild Dehydration

44
Q

Pale Yellow Urine?

A

Good Hydration, Mild Dehydration

45
Q

Bright Yellow

A

Mild or Moderate Dehydration + Vitamin Supplements

46
Q

Orange - Amber

A

Moderate or Severely Dehydrated

47
Q

Tea-colored

A

Severe Dehydration

48
Q

What is Excretion?

A

Process of separating wastes from
body fluids, and then eliminating the waste.

49
Q

What does the Excretory System Do? What are its Functions? Main Organs?

A

regulates volume and
composition of body fluids.
excreting metabolic waste,
maintenance of water-salt balance (kidneys
regulate salts in blood and also blood pressure)
Maintenance of acid-base balance (kidneys
keep blood pH at 7.4), secretion of hormones.
 Main organs: kidney, bladder, ureters, sphincter
and urethra

50
Q

Urinary System In
SUMMARY

A

Kidneys produce
urine
2. Ureters transport
urine
3. Urinary bladder
stores urine
4. Urethra passes urine
outside

51
Q

What happens if one kidney is damaged or removed?

A

We have two, but if one is removed or
damaged, the other can increase in
size and take on workload.

52
Q

What is the kidney’s principle function?

A

Filtering blood and removing metabolic waste

53
Q

What are the kidney’s secondary function

A

Control water balance & pH
 Regulate blood levels of sodium, potassium,
bicarbonate, calcium ions
 Secretes erythropoietin to stimulate red
blood cell production
 Activate vitamin D production in skin

54
Q

Renal Artery vs Renal Vein Function?

A

Renal artery: from aorta to
kidneys
 Renal Vein: returns ‘clean’
blood to body

55
Q

Renal Cortex vs Renal Medulla

A

Renal Cortex: outer layer of
the kidney
 Renal Medulla: inner layer of
the kidney, contains cone
shaped tissue masses

56
Q

Renal Pelvis, Nephron

A

Renal Pelvis: central
space/cavity continuous with
ureter (which transports urine
to bladder)
 Nephron: tiny filters

57
Q

Nephron, how many per kidney? What is it referred to as?

A

THE NEPHRON – FUNCTIONAL
UNIT OF THE KIDNEY (10 to the power of 6 PER
KIDNEY)

58
Q

What is Glomerulus Filtration

A

1) Glomerular filtration:
Glomerulus filters
water and solutes (not
proteins) from blood
plasma into the
nephron, specifically the
Bowman’s capsule.
The filtrate is exactly
like plasma, just no
blood cells or proteins

58
Q

Tubular Reabsorption?

A

Filtrate passes through proximal
tubule and is reabsorbed. Actively
reabsorbs: nutrients (glucose,
amino acids), ions (Na, K).
Passively reabsorbs: water,
negative ions. Actively Secretes:
hydrogen ions

59
Q

Loop of Henle?

A

Descending Loop of Henle:
enters salty environment (medulla)
permeable to water and slightly to
ions. Water diffuses to capillaries.
 Concentration of sodium ions hits
maximum concentration at bottom
of loop.
 In the Ascending loop of Henle,
no longer water permeable,
instead ions diffuse into nearby
blood vessels.

60
Q

Tubular
Secretion

A

In Distal Tubule: also
part of tubule
reabsorption absorbs
water and sodium ions
based on the body’s
needs.
K+, H+ are secreted into
the distal tubule in order to
maintain pH. Other
substances like medicine
are also secreted into
the distal. All of this is regulated by hormones

61
Q

Urine Output

A

Permeability of distal tubule and collecting
duct is controlled by ADH (antidiuretic
hormone)
 ADH increases permeability which allows
more water to be removed from filtrate
and conserve water in body
 When body needs to eliminate excess
water, ADH is inhibited
 Drugs and caffeine block release of ADH
which increases volume of urine

62
Q

Kidney and Blood Pressure

A

Kidneys can adjust blood pressure by adjusting
blood volume.
 Low Blood Pressure: detected by juxtaglomerular
apparatus which releases the enzyme renin which
causes angiotensin to be released.
 Angiotensin:
1) Constricts blood vessels
2) Activates aldosterone
 Aldosterone: acts on nephrons to increase Na+
causing the osmotic gradient to increase. This
means more water moves out of nephrons.
Homeostasis accomplished.

63
Q

PH BALANCE

A

Our pH is constantly around 7.4 thanks
to our kidney
 Our bodies have a buffer system , any
excess H+ ions buffered by bicarbonate
ions in blood which form a less acidic
carbonic acid.
 Kidneys help restore the buffer by
reversing the reaction. Nephrons
recombine bicarbonate ions and restore
them to the blood.

AP Biology (9 decks)

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