Homeostasis Flashcards
What is homeostasis?
Homeostasis is the regulation of conditions in the body to maintain a stable internal environment in response to changes in both external (e.g. temperature) and internal (e.g. blood glucose levels) conditions.
Why do we need homeostasis?
Conditions in the body have to be kept stable as cells need the right conditions to function properly, e.g. enzymes get denatured if they’re too hot.
What is negative feedback?
Negative feedback is an automatic control system to keep your body conditions stable. A receptor detects if a stimulus - level is too high, the coordination centre recieves and processes this info and organises a response, which is carried out by the effectors, which counteract these changes.
How does the body regulate temperature?
Temperature receptors in the skin detect if the core body temperature is too high. This info is sent to the thermoregulatory centre in the brain and effectors are triggered to produce a response, e.g. sweating. Some of these systems work antagonistically, e.g. one effector cools and another heats, in order to achieve a very precise temperature.
What does the body do to cool you down?
Sweat is produced by sweat glands, which evaporates from the skin, transferring energy to the environment. The blood vessels supplying the skin also dilate so more blood flows to the skin. This is vasodilation, and it helps transfer heat to the surroundings.
What does the body do to heat you up?
Hairs stand up to trap an insulating layer of air, no sweat is produed, blood vessels supplying skin capillaries constrict to cut off the flow of blood to lessen the amount of heat transferred to surroundings, and the muscles contract automatically (shiver), which requires respiration, which helps transfer some energy to heat the body.
What are hormones?
Hormones are chemical messengers released into the blood directly. They are carried to other parts of the body but only affect specific cells or organs (called target organs). They are produced in various glands making up the endocrine system and have fairly long-lasting effects.
What is the pituitary gland?
The pituitary gland is by the brain, and produces many hormones that regulate body conditions. It is called the “master gland” because these hormones act on other glands, directing them to release hormones to bring change.
What is the thyroid?
The thyroid is located by the neck. It produces thyroxine, which regulates things such as rate of metabolism, heart rate and temperature.
What is the adrenal gland?
The adrenal gland is by the kidneys, and produces adrenaline to prepare the body for “fight or flight”.
What is the pancreas?
The pancreas is an organ which produces insulin, which is used to regulate blood sugar levels.
What is the role of the testes and ovaries in homeostasis?
The ovaries and testes produce the sex hormones oestrogen and testosterone. Oestrogen is involved in the menstural cycle, whilst testosterone controls puberty and sperm production in males.
What’s a blood sugar level?
Eating foods containing carbohydrates puts glucose into the blood. Metabolism of cells removes glucose from the blood, and exercise can remove much more glucose. Excess glucose is stored as glycogen in the liver.
What does the body do to manage blood glucose levels?
When there is blood with too much glucose, insulin is secreted by the pancreas. Glucose moves from the blood into the liver and muscle cells, and insulin tells the liver to start turning glucose into glycogen, removing glucose and storing it for later. When the opposite happens, glucagon is added (when the GLUCose is GONe). It’s secreted by the pancreas, and the glucagon tells the liver to start turning glycogen into glucose.
What does diabetes type 1 do?
Type 1 diabetes is where the pancreas produces little to no insulin. Blood glucose levels can rise to a level that can kill them as a result. People with type 1 diabetes require insulin therapy, where they recieve injections of insulin throughout the day, usually at mealtimes to stop the digested glucose from getting too high. It’s very effective, and the amount varies on what a person eats and how active they are. People with type 1 diabetes also have to think about what they’re eating, limit simple carbs and take regular exercise.
