Homeostasis and response Flashcards
Describe what homeostasis is and why it is important stating specific examples from the human body
Homeostasis - the regulation of the conditions inside your body and cells. It maintains a stable internal environment in response to changes in internal and external conditions. It maintains optimal conditions for enzyme action.
Describe the common features of all control systems
Describe the endocrine system, including the location of the pituitary, pancreas, thyroid, adrenal gland, ovary and testis and the role of hormones
Endocrine system - made up of glands that secrete chemicals (hormones) directly into the bloodstream, which carries them to the target organs.
Pituitary gland - brain - stimulates other glands
Pancreas - ? - produces insulin
Thyroid - neck - produces thyroxine
Adrenal gland - above kidneys - produces adrenaline
Ovary - produces oestrogen - ovaries
Testis - produces testosterone - testicles
State that blood glucose concentration is monitored and controlled by the pancreas
Insulin and glucagon control blood glucose levels. If the blood has too much glucose the pancreas secretes insulin to lower the blood sugar level. And if the sugar levels are too low glucagon is secreted by the pancreas.
Describe the body’s response when blood glucose concentration is too high
When the blood sugar is too high the pancreas detects high blood glucose and secretes insulin. The insulin causes the glucose to move into cells and this makes the liver turn glycogen into glucose which is then stored into the muslces and liver. This therefore reduces the blood glucose level.
Explain what type 1 and type 2 diabetes are and how they are treated
Type 1 - pancreas produces little or no insulin. Blood glucose can rise to dangerously high levels. Insulin injections required.
Type 2 - cells no longer respond to insulin properly. Blood glucose can rise to dangerously high levels. Carbohydrate controlled diet and regular exercise.
HT ONLY: Describe the body’s response when blood glucose concentration is too low
Glucagon is secreted by the pancreas which makes the liver turn glycogen into glucose which is released from the liver. This therefore increases blood glucose.
HT ONLY: Explain how glucagon interacts with insulin to control blood glucose levels in the body
Glucagon and insulin work in a negative feedback cycle.
Describe what happens at puberty in males and females, inc knowledge of reproductive hormones
Puberty - when the body starts releasing sex hormones, which trigger the development of secondary sexual characteristics (e.g. facial hair in men and breasts in women)
Men - main reproductive hormone is testosterone, which stimulates sperm production.
Women - the main reproductive hormone is oestrogen.
Describe the roles of the hormones involved in the menstrual cycle (FSH, LH and oestrogen)
FSH - causes egg to mature in ovary.
LH - stimulates ovulation.
Oestrogen - causes uterus lining to grow.
HT ONLY: Explain how the different hormones interact to control the menstrual cycle and ovulation
HT ONLY: Explain how hormones are used to treat infertility, inc the steps in IVF
The woman is given FSH and LH to stimulate several eggs to mature. The eggs are collected from the woman’s ovaries. The eggs are fertilised in a lab using the man’s sperm. The fertilised eggs are gown into embryos. Once the embryos are tiny balls of cells, one or two of them are transferred into woman’s uterus.
HT ONLY: Evaluate the risks and benefits of fertility treatments
Risks - can lead to multiple births, dangerous for mother/babies.
Benefits - helps women get pregnant
HT ONLY: Describe the functions of adrenaline and thyroxine in the body, and recall where they are produced
Adrenaline - produced in adrenal glands. Released in response to fear and stress. Increases heart rate and supple of O2 and C6H12O6 and readies the body for ‘fight or flight’.
Thyroxine - produced in the thyroid gland. It regulates the basal metobolic rate and is important for protein synthesis for growth and devopment.
HT ONLY: Explain the roles of thyroxine and adrenaline in the body as negative feedback systems
Thyroxine -
