Module Eight - Non-infectious Disease and Disorders Flashcards
Homeostasis Causes and Effects Epidemiology Technologies and Disorders
what is homeostasis?
maintenance by an organism of a relatively constantly internal state, regardless of external changes in the environment
what is the purpose of homeostasis?
allows organisms to function at their optimal metabolic efficiency despite changes in the external environment
why is homeostasis important?
it is essential that internal conditions be maintained in order for enzymes to perform at optimal metabolic efficiency
which body systems are involved in homeostasis?
- nervous system
- endocrine system
what does tolerance limits in homeostasis refer to?
the narrow range that variables that are maintained by homeostasis can be
what is a set point in homeostasis?
the ideal/regular value for variables that are maintained by homeostasis
what is the negative feedback system?
a self-regulating mechanism that maintains balance or homeostasis as a coordinated response or series of responses to a stimulus or stimuli
what are the two main stages of homeostasis?
- detecting change
2. counteracting the change
what cells detect a change in the internal environment of the body?
sensory cells/receptors
what is a change in the internal environment called?
stimulus
what are the steps in the negative feedback system?
stimulus –> receptor –> control centre –> effectors –> response
what is the role of the control centre in homeostasis?
analyses messages and initiates actions
how does the control centre initiate action in homeostasis?
sends directions through nerves/hormones to the effectors
what do the effectors in homeostasis include?
muscles, organs and glands
what is the main part of the control center in homeostasis?
the hypothalamus
which system releases hormones as a response to a stimulus?
endocrine system
which system releases nerve impulses as a response to a stimulus?
nervous system
What is important for living organisms to control?
- quantities of waste (eg. nitrogenous wastes)
- oxygen and carbon dioxide concentrations
- repair of damaged cells
- removal of malfunctioning cells, pathogens and foreign substances
- input and output of water
- concentrations of nutrients such as glucose
- concentrations of dissolved salts and minerals
- body temperature and metabolic rate
What is the hypothalamus?
It is a part of the brain that controls certain metabolic processes; secretes certain hormones and links the nervous system to the endocrine system via the pituitary gland.
What is the nervous system?
A complex system of nerves and cells that carry messages to and from the brain and spinal cord.
What is insulin?
A hormone made by the pancreas that helps maintain homeostasis of blood glucose levels.
What is glucagon?
A hormone made by the pancreas that prevents blood glucose levels from dropping too low.
What hormones is the pancreas responsible for?
- insulin
- glucagon
How does insulin function?
- it lowers blood glucose levels by facilitating glucose transport from the blood into the cells.
- after a meal the blood glucose levels rise because the carbohydrates in the food are digested and absorbed
What is the difference between a positive feedback mechanism and a negative feedback mechanism?
- a positive feedback mechanism is the exact opposite of a negative feedback mechanism.
- with negative feedback the output reduces or inhibits the original effect of the stimulus. In a positive feedback system the output enhances the original stimulus.
- eg. blood clotting - once a vessel is damaged platelets start to cling to the injured site and release chemicals that attract more platelets. the platelets continue to pile up and release chemicals until a clot is formed.
What are protein channels?
These allow the transport of specific substances across the cell membrane.
What is thermoregulation?
processes designed to maintain core internal temperature and return the body to homeostasis
What is adipose tissue?
Connective tissue in which fat is stored
What is vasoconstriction?
The narrowing of the diameter of blood vessels to slow down the flow of blood, which increases the blood pressure.
What is vasodilation?
The widening of the diameter of blood vessels to increase the flow of blood.
What is the endocrine system?
A collection of glans that secrete hormones directly into the nervous system
What is a steriod?
A group of hormones derived from cholesterol
What is the importance of homeostasis?
living organisms are exposed to frequent changes in their external environment. the internal envrionment is also constantly changing
despite these changes organisms must be able to maintian a constant internal environment
What is the importance of homeostasis?
living organisms are exposed to frequent changes in their external environment. the internal environment is also constantly changing. Despite these changes organisms must be able to maintain a constant internal environment for optimum metabolic activity
Eg. high level of efficiency of running cells, enzymes must have the optimum temperature and pH conditions.
What are behavioral adaptations in endotherms that aid in the maintenance of homeostasis? (temperature regulation)
- burrowing
- nocturnal activity
- seeking shade
- cooling down in water
- stretching out to increase the surface area for heat loss
- hibernation
- migration
- curling up in a ball or huddling together to decrease
What are structural adaptations in endotherms that aid in the maintenance of homeostasis? (temperature regulation)
- large ears increase the surface area for evaporative heat loss
- a large surface area to volume ratio helps to maximise heat loss
- insulation such as fat layers, blubber, hair, fur and feathers
- a smaller surface area to volume ratio to minimise heat loss
What are physiological adaptations in endotherms that aid in the maintenance of homeostasis? (temperature regulation)
- sweating to increase evaporative heat loss
- increased blood flow to the extremities: more blood enters the skin capillaries and heat is lost
- reduced blood flow to extremities which keeps the core of the body warm
- shivering causes rapid contraction and relaxation of skeletal muscles resulting in more heat being generated
- increases in metabolic activity
What is an endotherm?
Endotherms use internally generated heat to maintain body temperature. Their body temperature tends to stay steady regardless of environment.
What is an ectotherm?
Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment.
What are examples of endocrine glands?
- hypothalamus
- pituitary gland
- thyroid
- adrenals
- pancreas
- ovaries
- testes
What does adrenaline do?
- increases heart rate
- increases blood pressure
- changes the body’s metabolism
What does cortisol do?
- it is a steroid hormone
- regulates processes such as metabolism and immune response
What is antidiuretic hormone (ADH)?
- brings about reabsorbtion of water within the body
What is aldesterone?
- brings about the retention of salts within the body
What hormones work together in maintaining water balance?
- antidiuretic hormone
- aldosterone
Provide an example of how neural pathways allow homeostasis to be maintained?
Most of the signals that the human body uses to regulate body temperature are sent through the nervous system.
Provide an example of how hormones allow homeostasis to be maintained?
Blood glucose levels are maintained through hormone signalling.
What is the key difference between the nervous system and the hormone system?
- signals are sent throughout the body in two main ways
- the first is through nerves of the nervous system where they are sent as nerve impulses that travel through nerve cells called neurons
- these impulses are sent to other neurons or specific target cells at a location in the body that the neuron extends to
- the second way is through the circulatory system.
- these signals are transmitted by specific chemicals (hormones) which travel through the circulatory system