homeostasis Flashcards
what is homeostasis
in mammals it involves the physiological control systems that maintain the internal environment within restricted limits
what is the importance of homeostasis
to function properly and efficiently, maintenance of optimal conditions for enzyme action and cell function
what detects info about conditions inside and outside the body
sensory cells
what two coordination systems are used in the homeostasis mechanism
Nervous system and endocrine system
what is the nervous system
CNS and PNS, nerve impulses pass along neurones
what is the endocrine system
hormones (chemical substances) carried in the blood, to do with functions that don’t need instant responses
what is the importance of a stable core body temperature
vital for enzyme activity
what effect would a low temp have on enzyme activity
prevent or slow down reactions, less frequent collisions
what effect would high temps have on enzyme activity
speeds up reactions, higher frequency of collisions, too high temps cause enzymes to denature
what does a denatured enzyme mean
bonds (e.g h bonds) break causing a change in the tertiary structure of the enzyme which damages the active site
what effect does PH have on enzyme activity
extreme PHs denature enzymes
what is the importance of stable blood glucose
affects water potential and availability of respiratory substrates for cells, essential for cellular respiration
what is the role of negative feedback
to maintain homeostatic balance
what do negative feedback loops involve
a receptor to detect a stimulus, coordination system to transfer information and an effector to carry out a response
what do negative feedback loops do
reduce the effect of the original stimulus
what do positive feedback loops do
enhance the effect of the original stimulus
what is blood glucose controlled by
two hormones secreted by endocrine tissue in the pancreas called the islets of Langerhans
what do the islets of Langerhans contain
two cell types, a cells which secrete glucagon and b cells which secrete insulin
when is glucose released
when blood glucose concentration is high
what do muscle cells, fat cells and liver cells posses that aid in the action of insulin
glucose transporter proteins (target cells of insulin)
what do glucose transporter proteins do (GTP)
allow the uptake of glucose via facilitated diffusion
GTP are ……
insulin sensitive
what is the action of insulin
insulin binds to receptors on the surface of target cells, activates GTP, permeability of cells to glucose increases and so does the rate of facilitated diffusion, glucose enters cells and causes glycogenesis
what is glycogenesis
A glucose enters liver cells and an enzyme converts it to glucose phosphate, different enzymes convert glucose phosphate into glycogen, lowers concentration of glucose within liver cell, steep diffusion gradient is maintained between blood in capillaries and liver cell
