Homeostasis and Glucose Regulation Flashcards
Homeostasis
The ability for an organism to seek and maintain a stable environment, regardless of external changes.
What’s controlled to acheive homeostasis?
Temp, glucose, pH, water
Optimum and tolerance range
Optimum - Organism thrives
Tolerance - Organism can survive but not most efficiently
Niche
Interrelationship between a species and all abiotic and biotic factors in its environment
Physiological stress
The organisms response to a stressor, leads to a threat to homeostasis.
Stimuli receptors
Gather information about the body and environment (Exteroceptors and Interoceptors)
The main types of receptors and purpose
Chemoreceptor - Chemical stimuli
Mechanoreceptor - Mechanical stimuli
Photoreceptor - Light
Thermoreceptor - Heat or cold
Nociceptor - Pain
Osmosis - Water
Communication systems
Messages sent throughout the body to respond
(e.g. impulse travels through your nerves)
Control center
Receives information from the receptors
(e.g. Hypothalamus interprets he stimulus)
Effectors
Body part that changes its activity
(e.g muscles in hand stretch/contract abruptly)
The principle of feedback
Feedback systems are mechanisms that maintain homeostasis by returning an environment back to its tolerance or optimum range
Stimulus response model
Stimulus (input, change to environmnt)
- Receptor (detects stimuli)
- Processing center (processes info from receptor -> sends message to effector)
- Effector (carries ou the response)
- Response (output, returns organisms to tolerance range)
Negative feedback loop and examples
Process where your body reverses a change that is occurring
- If temp decreases .. you will shiver to generate heat
- If temp increases … you will sweat to lose heat
Hypothermia
Temperature below 35 degrees
Convection
occurs when colder air move past areas of a warmer body
Conduction
Heat is lost to a thin layer of still air, water or solid that is in direct contact with a warm body
Radiation
Heated objects radiate heat as electromagnetic radiation
Evaporation
water from persons skin changes from liquid to gas
- Requires heat energy
Piloerection
Is an involuntary response that can occur when a mammal is fearful, aggressive, in shock or cold environment (goose bumps)
Shivering
involuntary action occuring when someone is exposed to cool air or water for extended period of time. Contraction and relaxation.
Brown Adipose tissue metabolism
They can break down fatty acids, releasing 100% of energy as heat (with no production of ATP)
Hyperthermia
Core body temp it’s above upper end of normal 38%
Heat stroke
Life threatening condition where brain function is effected, body is above 40 degrees
symptoms: slurred speech, hallucinations, organ damage
Heat exhaustion
increase in core body temp
symptoms: poor coordination, slower pulse, excessive sweating, can develop into heat stroke.
Sweating
water evaporates from liquid to gas. Evaporation of sweat requires energy, and energy is taken from blood vessels close to skin cooling body down.
Panting
Increase in breathing rate (reduce body temp through evaporation)
Temp decrease - stimulus response model
- stimulus
Decrease in body temp below normal - Receptor
Decrease detected by thermoreceptors in skin, organs and hypothalamus of brain - Control Center
Hypothalamus sends signals via nerve and hormonal systems effectors. - Effectors
Blood vessels in skin, Skeletal muscles, Brown adipose tissue - Response
Reduced blood flow in skin, Shivering, BAT Metabolic heat production.
Temp Increase - Stimulus response
- Stimulus
Increase in body temp above normal - Receptor
Increase detected by thermoreceptors in skin, organs and hypothalamus. - Control center
Hypothalamus sends signals via nerves to effectors - Effectors
Blood vessels in skin, sweat glands - Response
Vasodilation of skin vessels, initiation of sweating, inhibition of BAT metabolism.
Positive feedback loop
Process where body encourages change
Positive feedback loop
Process where body encourages change. (reinforces or increases stimulus)
e.g. pregnancy contractions
High glucose levels - stimulus response
- Stimulus
Increase blood glucose - Receptor
Beta cells of pancreas - Control center
Beta cells of the pancreas secrete the hormone insulin - Effectors
Skeletal muscle, adipose tissue, liver - Response
Decrease in blood glucose by:
Uptake of glucose by muscle and adipose tissue (cell channels are opened by insulin), glycogen formation in liver.
Decrease glucose levels - stimulus response
- Stimulus
Decrease blood glucose - Receptor
Alpha cells of pancreas - Control center
Alpha cells of pancreas secrete hormone glucagon - Effectors
Liver cells, body cells - Response
Increase in blood glucose by:
Release of glucose into blood from liver
Temporary homeostasis disruptions
Infections, fever, sore throats, muscle soreness
Major homeostasis disruptions
Frost bite: sensors are destroyed
Paralysis: messages from brain can’t travel through spinal cord if damaged.
Diabetes
Body is unable to automatically regulate blood glucose concentration
Hyperglycaemia
Glucose levels remain above optimum point (excess glucose excreted in urine)
- Inject insulin
Symptoms:
Increased thirst, frequent urination, extreme hunger, fatigue
Hypoglycaemia
Glucose levels are too low.
- Eat glucose (carbs)
Symptoms:
Fatigue, faint, sweating, dizziness.
Glycogenesis
When liver converts glucose to glycogen to then store.
