Homeostasis Flashcards Preview

Grade 12 LS 2016 > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (37):
0

What is tissue fluid?

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

1

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

  • Water
  • Oxygen
  • Carbon dioxide
  • pH
  • Temperature
  • Nutrients
  • Hormones
  • Excretory waste

2

The importance of maintaining constant water levels in tissue fluid

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

3

The importance of maintaining high oxygen levels in tissue fluid

  • Affects the rate of cellular respiration
  • and the rate of energy production

4

The importance of maintaining low carbon dioxide levels in tissue fluid

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

5

The importance of maintaining homeostasis of pH levels in tissue fluid

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

6

The importance of maintaining homeostasis of temperature in tissue fluid

Optimum temperatures required for enzyme functioning.

7

The importance of maintaining nutrient levels in tissue fluid

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

8

The importance of maintaining low excretory waste levels in tissue fluid

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

9

Examples of organs responsible for maintaining tissue fluid homeostasis

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

10

The maintaining of constant internal environment in the body

Homeostasis

11

Negative feedback mechanism

  • 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

The regulation of the body temperature of an organism.

Thermoregulation

13

ectothermic

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

14

Endothermic animals

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

15

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

Denature

16

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

Cellular respiration

17

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

Radiation

18

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

Convection

19

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

Conduction

20

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

Evaporation

21

Epidermis

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

22

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

Keratin

23

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

Malpighian layer

24

Melanin

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

Example ectothermic animals

Fish, amphibians and reptiles

26

How reptiles regulate body temperature.

  • Colour and body orientation to the sun
  • Dark colours absorb more heat,
  • pale colours reflect the sun's rays better

27

Example endothermic animals

birds and mammals

28

Advantage of being endothermic

Active both in cold and warm environmental conditions

29

Cornified layer of epidermis

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

30

Granular layer of epidermis

Layer under cornified layer with living cells

31

Malpighian layer of epidermis

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

32

Dermis

Layer beneath epidermis that contains: 

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

33

Blood vessels in dermis

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

34

Lymph vessels in dermis

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

35

Nerves in dermis

  • 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

Sensory organs in the dermis

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