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Biology > Unit 5 biology > Flashcards

Unit 5 biology Flashcards

1
Q

What is homeostasis

A

The maintenance of the body’s constant internal environment that uses negative feedback systems to keep it in balance

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2
Q

What 4 things does homeostasis control

A

-Blood glucose concentration
-Body temperature
-Water levels
-Hormone levels

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3
Q

What do automatic control systems do

A

detect changes in the body by using neural and hormonal communications

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4
Q

What 3 things do all control systems have

A

Receptors, coordination centers, effectors

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5
Q

How do receptors work

A

They detect stimuli and convert them into electrical impulses

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6
Q

Difference between sensory and motor neurons

A

Sensory neurons take electrical signals to the Coordination centre.
Motor neurons take electrical signals from coordination centres

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7
Q

How do coordinations centres receive information and what do they do with it

A

Electrical signals travel up sensory neurons up to the CNS where it processes the information and sends another electrical impulse

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8
Q

How do effectors work

A

Electrical signals from the CNS are sent along motor neurons and the effectors carry out the response

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9
Q

Why does the body have reflex arcs

A

To make sure that we receive minimal damage from sources of danger such as boiling water

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10
Q

What are synapses

A

Gaps between neurones where information gets transferred across

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11
Q

How does a synapse work

A

When the impulse reaches the end of the first neuron, chemicals are released and move across the synapse. When the chemical reaches the second neuron, the impulse restarts

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12
Q

How do we test reaction time

A

Ruler drop test

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13
Q

Describe the cerebral cortex

A

Cerebral cortex- controls consciousness, intelligence, memory and language. The outer part of the brain

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14
Q

Describe the cerebellum

A

Controls the fine movement of muscles. A round structure at the back of the brain

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15
Q

Describe the medulla

A

Controls unconscious action such as breathing and heart rate. Found in the brain stem.

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16
Q

Why so it difficult to investigate the brain

A

-complex and delicate
-easily damaged
-membranes around the brain stop drugs from getting to it
-we still don’t know everything each part of the brain does.

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17
Q

How can neuroscientists map out the brains structure

A

-studying patients with brain damage as if we know what part of the brain is damaged, we know what is does
-MRI scan make detailed images of the brain
-electrically stimulating the brain with electrodes to see which parts are affected

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18
Q

What is negative feedback

A

When the body detects a change in hormone levels, it counteracts the changes to return the body to normal levels.

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19
Q

Describe the retina in the eyes

A

Layer of light sensitive cells at the back of the eye. When light hits it, it stimulates the cells to send a signal to the brain in order to render an image

20
Q

Describe the optic nerve in the eyes

A

The nerve that leads from the eye, to the brain which carries the impulses made by the retina

21
Q

Describe the sclera in the eyes

A

White outer layer which supports the rest of the eye’s structure. Prevents dame to the rest of the eye

22
Q

Describe the cornea in the eye

A

Allows light through at the front of the eye. The curved face bends to focus light onto the retina.

23
Q

describe the iris in the eye

A

Muscles that expand and contract around the pupil.
The muscles expand in darkness to allow for better vision
The muscles contract in bright light to avoid retina damage

24
Q

describe ciliary muscles and suspensory ligaments in eyes

A

Holds the lens in place to control its shape

25
Q

How does an eye focus on a close up object

A

-Ciliary muscles contract
-Suspensory ligaments loosen
-lens thickens and curves to refract more light

26
Q

What do we call Short and long sightedness and how does it happen

A

Short sightedness- myopia; too curved lens so things appear blurry
Long sightedness-Hyperopia; lens is too flat so not enough light is refracted

26
Q

How does an eye focus on a far away object

A

-Ciliary muscles relax
-Suspensory ligaments tighten
-Lens becomes thinner to refract less light

27
Q

How does the thermoregulatory system work

A

Found in the brain and uses negative feedback systems.
Has receptors which monitor blood temperature and receptors on the skin.

27
Q

How can we treat issues with eyes

A

-Glasses lenses can spread of focus light more to help eyesight
-Contact lenses work the same as glasses but they wont fall out and are more versatile
-Laser eye surgery can reduce thickness of the cornea (myopia) or Change curvature of lens (hyperopia)
-Replacement lenses made of artificial glass can also be used

28
Q

What is human internal body temperature

A

37.5’C

29
Q

What happens if human body temperature exceeds 37.5’C

A

-Sweating is produced from sweat glands
-Vasodilation means more blood flows closer to the surface so more energy is released from the body

30
Q

What happens if human body temperature decreases too much

A

-Sweating stops
-Muscles expand and contract rapidly to avoid heat loss ( shivering)
-Vasoconstriction means less blood flows close to the surface so there is less heat loss

31
Q

How does the endocrine system transfer messages around the body

A

Glands secrete hormones directly into the bloodstream

32
Q

Name some glands in the body and what they produce

A

Thyroid- Produces thyroxine which controls metabolism and heart rate
Adrenal Gland- secretes adrenaline which controls fight or flight
Pancreas- produces insulin which regulates glucose levels

33
Q

Why is the pituitary gland special

A

It is the master gland and it stimulates the other glands to do their jobs

34
Q

What are the glands involved in reproduction

A

Ovary- secretes oestrogen and is involved in the menstrual cycle as well as developing female secondary sexual characteristics
Testes- Secretes testosterone and is involved with the production of sperm and male secondary sexual characteristics

35
Q

What is the response when glucose blood levels are too high

A

The pancreas produces insulin which stimulates glucose to move into muscles for respiration and to turn excess glucose into glycogen

36
Q

What is the response when glucose blood levels are too low

A

The pancreas produces glucagon which binds to liver cells causing glycogen to be broken down into glucose. the glucose is released into the blood which increases the concentration.

37
Q

How does your pancreas know the changes in these levels in order to produce the correct response

A

A negative feedback loop works to make sure these substances are always in balance

38
Q

What happens when a person has diabetes

A

they cannot control their blood glucose level

39
Q

How does type one diabetes work

A

The pancreas stops producing insulin and so blood glucose can reach fatally high levels. as this glucose needs to be lost somehow, it gets urinated out, leaving the individual very thirsty

40
Q

How can we treat type one diabetes

A

-Insulin injections at mealtimes which allows glucose to be takin in by the bloodstream.
-Sufferers can decrease the amount of simple carbs they eat to as they contain a lot of glucose
-Pancreatic transplants are starting to be made and so are artificial pancreases

41
Q

How does type 2 diabetes work

A

The body no longer responds to insulin so blood glucose levels can rise to fatal amounts. Obesity is a risk factor for type 2 diabetes

42
Q

How can we treat type 2 diabetes

A

-It can be sent into remission by reducing carb diets, losing weight and increasing exercise
-There are drugs to make the body less resistant to insulin or help the pancreas make more insulin

43
Q

Osmosis recap: what happens when water concentration is too high or low in the blood

A

When it is too high, water moves into cells via osmosis but there is still too much water to the cells burst.
When it is too low

44
Q
A

Biology (7 decks)

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