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Biology February Mock > Exercise And Feedback Mechanisms 7.11-7.16 > Flashcards

Exercise And Feedback Mechanisms 7.11-7.16 Flashcards

1
Q

What is homeostasis?

A

The mainetanance of a stable internal environment using control systems

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2
Q

What happens if body temperature becomes too high?

A

Enzymes become denatured - enzymes molecules vibrate too much which breaks hydrogen bonds holding them together so shape of aftive site is changed so no longer a catalyst = metabloic reactions are less efficient

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3
Q

What types of things does homeostasis control?

A

Temperature - vital for enzyme function
Blood glucose concentration - falls after exercise - monitored by pancreas
Water - monitored by kidneys

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4
Q

What is negative feedback

A

Where a change from a set point in one direction leads to a counteractive change in the opposite direction, returning to the set point

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5
Q

How does negative feedback work in homeostasis?

A

Receptors detect when level is too high or low
Communicated by nervous/hormonal system to effectors
Effectors counteract the change restoring normal level

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6
Q

What is positive feedback?

A

Where a change from a set point in one direction leads to further change in the same direction

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7
Q

How does positive feedback work?

A

Rapidly activates something

Eg. Platelets become activated and release a chemical that triggers more platelets

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8
Q

Why is a positive feedback mechanism not part of homeostasis?

A

Doesn’t keep your internal environment stable

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9
Q

What is thermoregulation?

A

Thermoregulation is a process that allows your body to maintain its core internal temperature

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10
Q

Describe mechanisms used to reduce body temperature x3:

A

Sweating: sweat secreted from sweat glands, water evaporates from surface of skin removing heat

Hairs lie flat: erector pili muscles relax so hairs lie flat, less air is trapped so skin is less insulated and heat can be lost more easily

Vasodilation: arterioles near the surface of the skin dilate so more blood flows through the capillaries in surface layer of dermis, more heat is lost by radiation and temp lowered

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11
Q

Describe mechanisms used to increase body temperature x5:

A

Shivering: muscles contract in spasms so more heat produced from increased respiration

Less sweat: less secreted so less heat lost

Hairs stand up: erector pili muscles contract which traps more air so prevents heat loss

Vasoconstriciton: arterioles near surface of skin constrict so less blood through capillaries in surface layers of dermis so less heat loss

Hormones: adrenaline and thyroxine release which increases metablosim so more heat produced

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12
Q

What part of the brain regulates body temperature?

A

The hypothalamus

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13
Q

How does the hypothalamus control body temperature?

A
  • Thermoreceprors send nerve impulses along sensory neurones to the hypothalamus
  • Hypothalamus sends impulses along motor neurones to effectors
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14
Q

What are transciption factors?

A

Proteins that control the trasncription of genes by binding to DNA sites near the start of genes and either increase (activator) or decrease (repressor) the rate of transcription

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15
Q

What affects the activity of transcription factors?

A

Hormones

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16
Q

Describe steroid and thyroid hormones

A

Work inside cells by crossing cell membrane, entering the nucleus and binding to transcription factors

17
Q

Describe what happens with the thyroid hormone in regulation of body temperature

A
  • at normal body temp, thyroid hormone receptor binds to DNA at start of gene
  • decreases the transcription of a gene coding for a protein that increases metabolic rate
  • at cold temp, throxine released which binds to thyroid hormone receptor causing it to act as an activator
  • trasncription rate increases, more protein produced, increased metabkoc rste, increased body temperature
18
Q

Why can steroid and thyroid hormones cross the cell membrane?

A

They are lipid-soluble

19
Q

Describe protein hormones:

A

Cannot cross the cell as they are not lipid soluble, so work from cell membrane

20
Q

How do protein hormones work?

A
  • bind to receptors in cell membrane
  • activate messenger molecules in cytoplasm of the cell
  • messengers activate enzymes callaed protein kinases which trigger a cascade inside cell
  • during cascade transcription factors are activated which effects trasncription of genes
21
Q

For analysis and data interpretation questions om exercise and health, see page 170-171

A

:)

22
Q

Describe keyhole surgery:

A

Surgeons make a small incision into patient and insert a video camera and specialised medical instrunments through the incision into the body

23
Q

Advantages of keyhole surgery:

A
  • patient loses less blood and less scarring
  • recovery time is quick due to less pain and less damage to body
  • hospital time is shorter so quicker return time to normal activities
24
Q

What ligament is commonly treated with keyhole surgery + where are they found?

A

Cruciate ligaments - found in the middle of the knee, connecting thigh bone to lower leg bone

25
Q

What can be done to damaged cruciate ligaments?

A

It can be removed and replaced with a graft - likely to be a tendon in the patients leg

26
Q

What do prostheses do?

A

Replace whole limbs eg. artificial leg

Replace part of limbs eg. artificial hip joints

27
Q

How do lectronic prstheses work?

A

They pick up info sent from nervous system

28
Q

How can a damaged knee joint be replaced by prosthetic joints?

A
  • metal device inserted into knee to replace damaged cartilage and bone
  • cushioning in new joint helpe to reduce impact on knee
29
Q

Name three types of perfromance-enhancing drugs:

A
  • anabolic steroids
  • stimulants
  • narcotic analgesics
30
Q

What are anabolic steroids?

A

Deugs that increase strength, speed, stamina and agression by increasing muscle size

31
Q

What are stimulants?

A

Drugs that speed up reactions, reduce fatigue and increase agression

32
Q

What are narcotic analgesics?

A

Drugs that reduce pain so that injuries don’t affect performance

33
Q

What are absolutists?

A

People that believe performance enhancing drugs should be banned from ALL sports as it is morally wrong

34
Q

What are rationalists?

A

People that believe performance enhancing drugs can be justified in certain circumstances

35
Q

What are the arguments AGAINST performance-enhancing drugs?

A
  • some are illegal
  • unfair advantage
  • serious health risks eg. high blood pressure
  • athletes not fully informed of risks
36
Q

What are the arguments FOR performance-enhancing drugs?

A
  • athletes have right to make own decision
  • drug free sports isn’t fair anyway, access to different training facilities, coaches, equipment
  • drugs allow for a higher level of performance

Biology February Mock (9 decks)

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