Homeostasis Flashcards Preview

Grade 12 LS 2020 > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (37)
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0
Q

Factors in tissue fluid that need to be kept constant (homeostasis)

A
  • Water
  • Oxygen
  • Carbon dioxide
  • pH
  • Temperature
  • Nutrients
  • Hormones
  • Excretory waste
1
Q

What is tissue fluid?

A
  • Body fluid found bathing the cells
  • (Called blood plasma in the blood vessels)
  • (Called lymph when found in the lymph vessels)
2
Q

The importance of maintaining constant water levels in tissue fluid

A
  • Water is medium for many chemical reactions
  • Prevents dehydration and death
  • Important for osmoregulation and maintaining turgidity
3
Q

The importance of maintaining high oxygen levels in tissue fluid

A
  • Affects the rate of cellular respiration
  • and the rate of energy production
4
Q

The importance of maintaining low carbon dioxide levels in tissue fluid

A
  • A waste product of cellular respiration
  • it must be excreted Its presence lowers the pH (more acidic)
5
Q

The importance of maintaining homeostasis of pH levels in tissue fluid

A

Optimum levels for enzyme activity between 7,0 and 7,4 for most enzymes

6
Q

The importance of maintaining homeostasis of temperature in tissue fluid

A

Optimum temperatures required for enzyme functioning.

7
Q

The importance of maintaining nutrient levels in tissue fluid

A
  • Needed for growth, repair and metabolism
  • Example: glucose, amino acids and fatty acids
8
Q

The importance of maintaining low excretory waste levels in tissue fluid

A

Waste products like urea and carbon dioxide need to be continually removed as these are toxic if accumulated

9
Q

Examples of organs responsible for maintaining tissue fluid homeostasis

A
  • Kidneys (osmoregulation - water and salt)
  • Lungs (carbon dioxide)
  • Pancreas and liver (glucose)
  • Skin (thermoregulation - temperature)
10
Q

The maintaining of constant internal environment in the body

A

Homeostasis

11
Q

Negative feedback mechanism

A
  • The mechanism involving the detection of a deviation from the normal state,
  • resulting in a reaction that counteracts the change and returns it to normal.
12
Q

The regulation of the body temperature of an organism.

A

Thermoregulation

13
Q

ectothermic

A

The group of animals with a body temperature varying according to the environmental temperature.

14
Q

Endothermic animals

A

The group of animals maintaining their body temperature, irrespective of the environmental temperature.

15
Q

The process during which enzymes, at high temperatures, lose their shape permanently and cannot fulfill their function.

A

Denature

16
Q

The maim source of heat generation in the human body, occurring in every living cell.

A

Cellular respiration

17
Q

The loss of heat energy by the body, from a warm body to a cold environment by rays or waves.

A

Radiation

18
Q

The loss of heat by the body when the surrounding air is warmed.

A

Convection

19
Q

The loss of heat from the body when energy is transferred from warm objects to cold objects in contact with one another.

A

Conduction

20
Q

The loss of heat from the body when sweat evaporates from the surface of the body and heat is absorbed from the skin.

A

Evaporation

21
Q

Epidermis

A
  • The external part of the skin, made up of layers which protects the underlying tissues.
  • Cornified, granular and Malpighian layers.
22
Q

The protein found in the outer epidermal cornified layer of human skin.

A

Keratin

23
Q

The bottom layer of the epidermis, made up of living cells.

A

Malpighian layer

24
Q

Melanin

A

The pigment in the bottom layer of skin that provides protection from the harmful UV rays of the sun and gives colour to the skin.

25
Q

Example ectothermic animals

A

Fish, amphibians and reptiles

26
Q

How reptiles regulate body temperature.

A
  • Colour and body orientation to the sun
  • Dark colours absorb more heat,
  • pale colours reflect the sun’s rays better
27
Q

Example endothermic animals

A

birds and mammals

28
Q

Advantage of being endothermic

A

Active both in cold and warm environmental conditions

29
Q

Cornified layer of epidermis

A
  • Outermost layer Dead, flattened, flaky cells
  • Contain keratin to protect skin from water light and infection
30
Q

Granular layer of epidermis

A

Layer under cornified layer with living cells

31
Q

Malpighian layer of epidermis

A
  • Living cells that divide to replace damaged and shed layers of skin
  • Contain pigment melanin
  • Cells supplied by tissue fluid from dermis
32
Q

Dermis

A

Layer beneath epidermis that contains:

  • blood and lymph vessels,
  • nerves,
  • sensory organs,
  • hair follicles,
  • tiny erector muscles
  • and glands.
33
Q

Blood vessels in dermis

A
  • able to constrict or dilate to help regulate body temperature
  • diameter controlled by vasomotor center in medulla oblongata
34
Q

Lymph vessels in dermis

A
  • Lymph capillaries in the dermis carry excess tissue fluid with waste products away from the skin
  • into larger lymph vessels
35
Q

Nerves in dermis

A
  • Sensor nerves conduct impulses from the skin to the CNS
  • Motor nerves conduct impulses from the hypothalamus to the muscles in the blood vessels
  • and to glands and erector muscles.
36
Q

Sensory organs in the dermis

A
  • Ruffini’s corpuscles detect heat
  • Krause’s corpuscles detect cold
  • Pacinian corpuscles detect pressure
  • Meissner’s corpuscles detect touch
  • Free nerve endings detect pain