homeostasis ! Flashcards
adrenal gland !
secretes adrenaline
adrenaline !
secreted in response to stress or excitement
allows body to respond quickly to sudden demands for energy
effects are temporary
adrenaline process !
hypothalamus in brain is stimulated -> transmission of nerve impulses to spinal cord
motor neurone transmits nerve impulses -> adrenal gland -> secretes adrenaline into bloodstream
blood : transports adrenaline -> target organs
adrenaline effects !
increases blood pressure & heart rate
increases blood glucose level : speed up breakdown of glycogen to glucose in liver & muscle cells
contracts hair muscles : goose pimples
constricts arteries in skin : paleness
- channel more blood to muscles
islets of Langerhans !
secrets insulin & glucagon
importance of maintaining blood glucose concentration !
glucose : required for tissue respiration -> releases energy for cells to carry out activities
insulin !
secreted when glucose concentration is above normal levels
promotes utilisation of glucose by cells : increases rate of glucose uptake by cells
- increases permeability of cell membranes to glucose
- stimulates liver & muscle cells to convert glucose -> glycogen for storage
- increases oxidation of glucose during tissue respiration
lack of secretion of insulin !
glucose : cannot be stored/utilised by tissue cells -> blood glucose concentration increases
- causes diabetes mellites
- muscle cells : do not have reserves of glycogen -> body grows weak & continuously loses weight
- body : oxidised fats instead of glucose to produce energy -> produces poisonous substances
over secretion of insulin !
abnormal decrease in blood glucose concentration
low blood glucose concentration -> coma & death may occur
diabetes mellitus !
disease in which the body is unable to control its blood glucose concentration within the normal range
insufficient insulin secretion to regulate blood glucose concentration -> high level of glucose in blood
kdineys : unable to completely reabsorb glucose in body -> glucose excreted in urine
signs of diabetes !
persistently high blood glucose level
presence of glucose in urine after meal
healing of wounds is slow & difficult
type 1 diabetes !
develops early in a person’s life
islets of Langerhans : unable to produce & secrete sufficient insulin
treatment : insulin injection
type 2 diabetes !
occurs later in a person’s life
target cells do not respond to insulin well
treatment : control of dietary intake, exercising
glucagon !
produced when blood glucose concentration is below normal levels increases blood glucose concentration : - glycogen -> glucose - fats & amino acids -> glucose - lactic acid -> glucose
