Topic 2: Body Balance Flashcards
What does the endocrine system do?
- maintains balance in the body through the
action of hormones
What is the endocrine system?
The endocrine system is made up of endocrine glands that secrete hormones which travel through the bloodstream to cells everywhere in the body. This allows for the maintenance of the internal environment in the body, or internal homeostasis
What does the endocrine system do?
It regulates, coordinates and controls:
1. growth and development
2. male and female development
3. how your body uses energy
4. Appetite
What is an endocrine gland?
A gland that secretes hormones into the bloodstream for transport around the body.
- same in males and females, except for the ovaries and testes.
What is a hormone?
chemical messengers that are secreted from the endocrine glands into the bloodstream for transport around the body
How do hormones “know” which cells are their target cells?
It is because target cells have special receptors that recognise the hormones and allow them to influence that cell.
What controls internal signalling?
Nerve Cells - are short acting but send a message quickly
Hormones - are long-acting but slower to be received.
What are target cells?
have receptors on the cell membrane of a cell that recognise hormones to initiate a response. It responds to the hormone when it binds to its receptors, triggering a specific cellular response
Role of the hypothalamus
- monitors the body for temperature, pH, and other conditions.
- signals the pituitary gland if conditions need to be corrected.
Role of the pituitary gland
- signals other glands to produce their hormones when needed
- found in the brain and receives signals from the hypothalamus.
Hormones released: pituitary gland
- Growth Hormone
- Too much - gigantism
- Too little - dwarfism - Antidiuretic hormone - stimulates kidneys to keep water
Role of the thyroid gland
- regulates metabolism and energy balance
Hormones released: thyroid gland
- Thyroxine - regulates body energy usage
- Calcitonin - regulates calcium and phosphate in the blood.
What does the thyroxine do?
- controls the rate of metabolic processes in the body and influences physical development.
Hormone Released: Adrenal Glands
- Adrenaline - stimulates heart rate, increases blood pressure, and dilates pupils (acts on multiple tissues).
- Cortisol: increases mental stimulation, and breaks down fat and protein to glucose. Involved in response to stress and anxiety
Role of Pancreas
- regulates blood sugar levels in the blood.
Define homeostasis
The body’s ability to regulate and maintain a stable condition inside your body, regardless of changes to the external environment
Name the 2 body systems that coordinate all the functions of the body
- the nervous system
- the endocrine system
3 Examples of homeostasis:
- body temperature at 37ºC
- the amount of water inside our body
- blood sugar levels
Why is it so important to maintain temperature?
The human enzymes work best at 37ºC, so if the body temperature changes too much, it could result in:
- heat stroke
- hyperthermia
- dehydration
- death
Why is it so important to maintain water levels?
If the amount of water in the body is wrong, cells can be damaged because too much water enters and leaves them, affecting their ability to function properly.
Why is it so important to maintain carbon dioxide levels?
increased CO2 levels would alter the concentration of CO2 and O2 and the cells wouldn’t receive enough oxygen which means they wouldn’t function properly.
SRBERN
Stimulus - what has happened?
Receptors - name the type of receptor
Brain - hypothalamus
Effector - fixes the problem
Response - counter-acts the problem
Negative Feedback - don’t want it to keep happening
What are the effectors involved if the body temperature is too low?
- Blood vessels will constrict
- Muscles will contract ( they will begin to shiver)
What are the effectors involved if the body temperature is too high?
- Sweat glands produce sweat
- Blood vessels dilate to release heat
What are the effectors involved if the blood-sugar levels are too high?
The pancreas produces more insulin which uptakes excess glucose from the blood to be stored as glycogen
What are the effectors involved if the blood sugar levels are too low?
The pancreas releases glucagon, which causes the liver to convert glycogen into glucose
how does the body maintain homeostasis?
- receptors - detect the changes
- control centre - recieve info and control the response
- effectors to produce a response
What is a negative feedback loop?
It is a response triggered by changed conditions and counteracts the change. It occurs to remove the original stimulus to maintain homeostasis.
Problem in Type 1 Diabetes
The immune system has destroyed beta cells, so no insulin is produced in the bloodstream to uptake excess glucose.
Problem in Type 2 Diabetes
The body cells that should take in glucose don’t, as they are resistant, causing glucose to remain in the bloodstream.
What is a positive feedback loop?
When a process keeps increasing its activity. It makes things happen faster or stronger until something big happens to stop it
Example of a positive feedback loop
Childbirth - The baby’s head pushing on the cervix leads to stronger contractions, which helps the baby to be born. Once the baby is born, the loop stops because the stimulus is no longer present
What controls the release of hormones?
- External Stimuli - via the nerves from the sensory organs in the nervous system
- Internal Stimuli - via nerves and other hormones from inside the body