receptors
SENSORS that detect the stimulus occurring to the body
control centre
ANALYSES INFO sent from the receptors, compares to the set point and determines a response
effectors
cell or organ that PRODUCES A RESPONSE under the instruction by the control centre
negative feedback
- responds to reduce or stop the undesirable initial stimulus
- most homeostatic control systems
- body temp, BP, blood sugar levels
positive feedback
- responds to enhance or continue initial stimulus
- less common
- childbirth, breast feeding, blood clotting
body’s response to increased body temp
Stimulus- hot day
- thermoreceptors in skin detect increase in skin temperature
- signal gets sent to hypothalamus
- blood vessels in skin signaled to vasodilate and sweat glands to sweat
Sweat
- sweat glands in skin produce sweat onto the skin surface
- heat transferred into the sweat
- heat is removed as the sweat evaporates
vasodilation
- increase blood vessel diametre
- blood flow closer to skin surface
- heat is transferred onto skin surface
- heat is lost from the skin surface by heat exchange mechanisms (conduction, convection, radiation)
body’s response to decreased body temperature
- thermoreceptors in skin detect decrease in skin temperature
2. hypothalamus gets signaled
3. skeletal muscles shiver, blood vessels in skin vasoconstrict
shivering
- muscles rapidly contracting
- shivering generates heat
vasoconstriction
- decrease blood vessel diametre
- decreased blood flor near skin surface > pale skin
- heat is conserved to warm the body and not lost onto skin surface.
body’s response to childbirth
- head of fetus presses on cervix
- receptors in cervix detect stretch
- message sent to brain
- release of oxytocin from pituitary gland
- oxytocin causes uterus to contract
dorsal cavity
- cranial cavity (brain)
- vertebral cavity (spinal cord)
ventral cavity
- thoracic cavity
> pleural cavity (lungs)
> pericardial cavity (heart) - abdominopelvic cavity
> abdominal cavity (digestive organs)
> pelvic cavity (bladder, reproductive organs, rectum)
serous membranes
- ventral cavities lined with serous membranes
- thin double layered membrane
> visceral layer covers organs
> parietal layer lines wall of cavity - reduces friction as organs move
serous membranes in cavities
In pleural cavity - pleura
In pericarial cavity - pericardium
In abdominopelvil cavity - peritoneum
directional terms anterior (ventral) posterior (dorsal) superior inferior
- towards the front
- towards the back
- towards the top
- towards the bottom
directional terms
media
lateral
intermediate
- towards midline
- away from midline
- between 2 points
directional terms proximal distal superficial deep
- closer towards point of origin
- further away from point of origin
- towards surface
- towards the inside
body planes - frontal
transverse
- vertical line that divides the body into anterior and posterior parts
- horizontal line that divides body into superior and inferior parts
body planes
sagittal
midsagittal
parasagittal
- vertical line that divides the body into left and right parts
- divides the body into equal left and right halves
- divides body into unequal left and right parts
levels of structural organisation
chemical cells tissues organs organ systems organism
simple > complex
necessary life functions
- movement
- responsiveness
- digestion
- metabolism
- excretion
- reproductive
- growth
