homeostasis and excretion Flashcards
What is homeostasis?
Homeostasis is the process of keeping conditions inside the body relatively constant.
what is the excretory product of the kidneys
urea
What are the main sources of water gain for the body?
Water gain comes from:
* drinking
* food
* cell respiration.
What are the main ways the body loses water?
Water loss occurs through:
* urine
* sweat
* faeces
* exhaled air.
Define tissue fluid.
Tissue fluid is a watery solution of salts, glucose, and other solutes that surrounds all the cells of the body.
What is the function of tissue fluid?
Tissue fluid forms a pathway for the transfer of nutrients between the blood and the cells.
What happens if tissue fluid contains too many solutes?
Cells lose water by osmosis and become dehydrated.
What is excretion?
Excretion is the process by which waste products of metabolism are removed from the body.
What is the main nitrogenous excretory substance in humans?
The main nitrogenous excretory substance is urea.
What are some examples of nitrogenous waste?
Examples of nitrogenous waste include:
* urea
* ammonia.
What is the role of the liver in protein metabolism?
The liver breaks down excess amino acids and converts them into carbohydrates and urea.
What is the body temperature of homeothermic animals?
Homeothermic animals maintain a constant body temperature, typically around 37 °C for humans.
What is the physiological term for ‘warm-blooded’ animals?
The term is homeothermic.
What part of the brain monitors body temperature?
The hypothalamus monitors body temperature.
What are the physiological responses to increased body temperature?
Responses include:
* increased sweat production
* vasodilation.
What is vasodilation?
Vasodilation is the widening of arterioles to allow more blood flows to the skin surface
(more) heat is taken to the surface and heat (energy ) is lost (from the skin)
What is vasoconstriction?
Vasoconstriction is the narrowing of blood vessels to reduce blood flow to the skin’s surface.
How does sweating cool the body?
sweat secreted on skin surface. evaporates due to latent heat of evaporation. energy supplied is body’s heat, cooling body down.
What is the role of the epidermis?
The epidermis forms a tough outer layer that prevents water loss and protects against pathogens.
What is the function of the dermis?
The dermis contains sensory receptors, sweat glands, blood vessels, and hair follicles.
What happens to hairs on the skin in cold conditions?
Hairs stand upright to trap a layer of air for insulation.
how does shivering generate heat
Shivering generates heat through rapid muscle contractions.
how does hair play a part in insulation
in cold conditions hair erector muscles contract pulling hair upright. this traps a layer of air next to the skin . air is a poor conductor of heat so this acts as a insulator.
Fill in the blank: The average body temperature of a human is ______.
37 °C
What is the core function of the hypothalamus related to temperature control?
It acts as the body’s thermostat.
What is the latent heat of vaporisation?
It is the energy required for a liquid to turn into gas during evaporation.
What is the main function of the hypodermis?
The hypodermis insulates the body and serves as an energy store.
What happens to the body’s metabolism during conditions that require heat generation?
The body’s metabolism speeds up, generating more heat.
The liver plays a significant role in producing metabolic heat.
Which hormone stimulates an increase in metabolism?
Adrenaline.
This is discussed in Chapter 7.
What physiological response occurs when the body shivers?
Muscles contract and relax rapidly, generating a large amount of heat.
Shivering is an important mechanism for thermoregulation.
List some mechanisms the body uses to maintain its temperature around 37 °C.
- Sweating
- Vasodilation
- Vasoconstriction
- Hair erection
- Shivering
- Changes to metabolism
- Behavioral actions
These mechanisms work together to keep body temperature stable.
What indicates that something is wrong with the body’s temperature regulation?
A temperature difference greater than a few tenths of a degree from the normal 37 °C.
For example, a temperature of 39 °C might indicate an illness.
Fill in the blank: The hormone _______ stimulates the increase in metabolism.
adrenaline
True or False: Shivering is a response that helps generate heat in the body.
True
What is the normal body temperature in degrees Celsius?
37 °C
thermoregulation
the process by which living organisms maintain a constant internal body temperature despite changes in environment.
