Chapter 7 Homeostasis Of Body Temperature And Body Fluids

Front 1

Define thermoregulation

Back 1

Maintaining body temperature by losing the same amount of heat that's gained

Front 2

Why is body temperature higher than the external environment?

Back 2

Metabolic activity produces a lot of heat

Front 3

Why does heat need to be removed?

Back 3

Highly increased temperature leads to nerve malfunction, a change in protein structures, and even death

Front 4

Define dynamic equilibrium

Back 4

Some factors contribute to heat gain, others to heat loss

Front 5

How does temperature variation occur?

Back 5

Activity, external temperature changes, body temperature cycle, menstruation, convection, conduction, radiation, evaporation of water from skin, breathing, urination and defecation

Front 6

Define metabolic rate

Back 6

Rate of energy release

Front 7

Which factors affect metabolic rate?

Back 7

1. Increased body temp of 1 deg. Increases rate by 10%

2. Stress - ANS and release of noradrenaline

3. Muscular activity during respiration

Front 8

How is energy released?

Back 8

By the anabolism of lipids, proteins, and carbs during cell respiration

Front 9

How is most energy used?

Back 9

1. Released as heat

2. Energy for muscles

3. Energy for active transport

Front 10

Define peripheral thermoreceptors

Back 10

Heat receptors in the skin and mucous membranes that sense the external temperature. There are cold and hot receptors.

Front 11

Define central thermoreceptors

Back 11

Heat receptors in the hypothalamus, abdominal organs, and spinal cord that sense internal temperature

Front 12

What special role do the thermo receptors in the hypothalamus play?

Back 12

They regulate body temp by responding to stimuli with nerve impulses. They are connected to all other thermo receptors and are stimulated to respond by peripheral receptors.

Front 13

What happens when cold receptors in the hypothalamus are stimulated?

Back 13

Heat conservation and production are initiated

Front 14

What happens when heat receptors in the hypothalamus are stimulated?

Back 14

Increased heat loss and reduced conservation

Front 15

Name the ways that heat can be lost

Back 15

1. Conduction

2. Convection

3. Radiation

4. Evaporation

Front 16

Define radiation

Back 16

The heat generated in the body is given off to the surrounding atmosphere

Front 17

Define conduction

Back 17

When heat is lost to something that is contacting the body

Front 18

Define convection

Back 18

Heat loss caused by motion

Front 19

Define evaporation

Back 19

When sweat/moisture evaporates from skin, heat is taken with it

Front 20

Why do blood vessels near the surface of the skin control the level of blood flow?

Back 20

1. Change level of heat loss for homeostasis

2. Keep core body temp constant

Front 21

Define sweating

Back 21

Active secretion of fluid by the sweat glands and periodic contraction of the cells surrounding the ducts to pump the sweat to the skin's surface

Front 22

Why does sweating occur?

Back 22

It occurs when heat still needs to be lost despite full vasodilation

Front 23

Define sweat

Back 23

Water containing solutes that allows for heat loss

Front 24

Which solutes are found in sweat?

Back 24

Sodium chloride, urea, lactic acid, potassium ions

Front 25

What physical reaction is there to a cold stimulus from the external environment?

Back 25

1. Cold receptors in skin send a message to hypothalamus

2. Hypothalamus sends impulses to reduce heat loss

3. Physiological and behavioural responses may occur