Topic 7 - Animal Coordination, Control And Homeostatis Flashcards
What are hormones?
Hormones are chemical messengers that are made in one part of the body and are carried in the blood to other parts of the body, where they affect.
Hormonal controlled system responses are (faster/slower) than…
Slower than nervous System controlled responses
Describe how endocrine glands communicate with organs around the body (2)
release chemicals called hormones into the blood which carries them around the body to target organs
Metabolism definition
All the chemical reactions that occur in your body
Metabolic rate definition
The overall rate at which chemical reactions occur in your body
Factors that affect metabolic rate
Anything that affects the amount of energy required e.g trying to keep warm, exercise, digesting food
Where and how much adrenaline is released?
The adrenal glands. Very little is released into the blood
Affects of adrenaline
Heart muscle cells contract more rapidly and more strongly.
Diameter of blood vessels leading to muscles widens.
Diameter of blood vessels leading to other organs narrows.
Liver cells change glycogen to glucose and release it into the blood.
Conditions required to measure metabolic rate
Gap in time since eating, warm room, no movement
Negative feedback - definition
A control mechanism that reacts to a change in a condition, such as temperature, by trying to bring the condition back to normal.
What does the hormonal system consist of, and what do they do?
Endocrine glands that produce and release hormones
What does the pituitary gland produce? Where is it found?
ACTH, FSH, LH, growth hormone. Found in the brain (cerebellum)
What does the thyroid gland produce, where is it found?
In the neck, it produces thyroxine.
What do cells in the pancreas produce
Some that produce insulin and others that produce glucagon
What do the adrenal glands produce
Adrenalin
What do the testes produce
Sex hormone - Testosterone
What do the ovaries produce
Sex hormones oestrogen and progesterone
What happens once a hormone has been produced?
Once the hormone has been produced by the endocrine gland, it will travel in the blood to the organ it affects. This is called a target organ.
What are the effects of thyroxine?
- It causes heart cells to contract more strongly and rapidly.
- It increases the rate at which proteins and carbohydrates are broken down inside cells.
Why is thyroxine an example of negative feedback?
- The amount of thyroxine produced by the thyroid gland is controlled by hormones. This is an example of negative feedback.
The Menstrual Cycle length
28 days
When does menopause begin/end?
puberty until menopause
What does the menstrual cycle enable females to be?
fertile
What is the menstrual cycle controlled by (hormones)
Sex hormones oestrogen and progesterone
What are oestrogen and progesterone released by
The ovaries into the blood
What does oestrogen do?
involved in repairing and thickening the uterus lining (leads to ovulation)
What does progesterone do?
maintains the uterus lining
What does FSH do?
causes the maturation of an egg in the ovary
What does LH do?
Stimulates the release of an egg
Where are FSH and LH released from?
The pituitary gland
What is the release of LH and FSH controlled by?
Oestrogen and progesterone
What is contraception?
The prevention of fertilisation
How does fertilisation of the egg occur?
- During sexual intercourse sperm cells enter the vagina.
- They pass through the cervix into the uterus and then into the oviducts.
- If the sperm cell meets an egg cell here, it may be fertilised.
The Sperm’s Journey
Sperm Duct
Penis
Vagina
Cervix
Uterus
Oviduct (where it will fertilise the egg)
Common reasons for infertility
Blocked fallopian tubes
Physical problems with the uterus
Low sperm count
Abnormal or immotile sperm
What does IVF mean and stand for?
In vitro fertilisation: fertilisation in the laboratory outside the mother’s body (Latin: ‘in vitro’ means ‘in glass’)