Hormones and homeostasis Flashcards
What is homeostasis?
The ability to maintain a constant internal environment
What does the hypothalamus monitor?
The temperature of the blood
What happens if the hypothalamus detects change in the temperature of the blood?
It sends signals via neurones to other organs, which will bring the temperature of the blood back to normal
Name 3 main ways the body controls the temperature
- sweating
- shivering
- controlling blood near skin surface
What do organs work together to keep constant?
Conditions in the tissue fluid around cells
What would happen if we didn’t have skin?
- wouldn’t be able to maintain a constant body temperature
- difficult for enzymes to react at optimum temperature
What would happen if we didn’t have lungs?
- gaseous exchange wouldn’t be possible
- no alveoli —> less efficient respiration
How do sensory neurones help with homeostasis?
- detect changing levels of solutes in blood
- signals go to hypothalamus
- feedback signals sent to organs
Explain what happens when the body is too cold
- capillaries vasoconstrict (reduces heat loss by radiation)
- hair erector muscles contract, hairs stand up, traps layers of air (reduce heat loss by reducing convection)
- no sweat is released
Explain what happens when body is too hot
- capillaries vasodilate (enlarge)
- higher blood flow at skin surface means increased radiation
- hair erector muscles relax, hairs flat, increased convection at skin surface
- sweat glands secrete sweat
- increased heat loss via evaporation
What does the liver control?
Levels of solutes in blood
What do the lungs control?
Exchange of carbon dioxide + oxygen
What do the kidneys control?
Water content of blood
What does the skin control?
Heat loss/gain
What do the intestines control?
Soluble foods and water
Where is insulin produced?
Pancreas
Where is adrenaline produced?
Adrenal glands
What is the pituitary gland controlled by?
Hypothalamus
What is a hormone?
- chemical messenger
- travels in the plasma
- travels to a target cell/organ
- initiates a change
Why is testosterone important?
For secondary sexual characteristic development
What hormones are produced in the ovaries?
Oestrogen and progesterone
What are is the effect and oestrogen/progesterone?
- make female secondary sexual characteristics develop
- involved in fertility/menstrual cycle
What 3 hormones are produced in the pituitary gland
- Follicle Stimulating Hormone (FSH)
- Luterizing Hormone (LH)
- Anti Diuretic Hormone (ADH)
What are is the effect of FSH and LH?
Effects fertility in the womb
