test 2
what is the heirarchy or complexity
specialised cell
tissue
organ
system
organism
what is epithelial tissue
sheets of cells that cover internal/external surfaces (outermost skin)
also form secretory parts of glands/ducts
functions of epithelial tissue
protection (skin)
absorbtion(small intestines lining)
secretion (glands)
what is muscle tissue
tissues that contract and enable movement (lots of mitochondria)
types of muscle tissue
cardiac (heart tissue/automatic)
skeletal/striated (biceps,triceps)
smooth (gut/arteries/automatic)
what is connective tissue
tissue that provide structural support and act as energy stores
what is nervous tissue
tissues made of diff nerve cells (neurons)
what does fluid connective tissue do
transport substances (blood/nymph)
what dods nervous tissue include
central nervous system
perioheral nervous system
enteric nervous system (gut and brain connection)
etc
what is nervous tissue responsible for
control/coordination of body / its function systems
what is the relationship between organs and tissues
organ is composed of diff groups of tissues (work cooperatively and perform specific functions)
lowest level/organisation
cellular
single layer body plan
middle level/organisation
tissue
two layer body plan
highest level/organisation
organ
three layer body plan
what is mechanical digestion
using physical factors like teeth it increases the SA:V ratio, creating better digestion
what is chemical digestion
uses chemical reaction to change foods into simpler substances for easier absorbtion
what role does epithelial play in gastro intestinal tract/organ walls
in the mucosa (innermost)
constantly renews in shapes of
squamos
cuboidal
columnar
with either simple or stratified (two or more) layers
what is connective tissues function in the gastro intestinal tract
in the submucosa (second layer)
and serosa (outermost layer)
absorbs and distributes absorbed substances
encapsulates solid organs of system
four layers of GIT/organ walls from inner to outer
mucosa (epithelial)
submucosa (lymph/blood - connective)
muscularis (muscle)
serosa (connective tissue)
muscle tissues function in gastro intestinal tract
multidirectional
forms muscularis (third layer)
two layers in layer
inner smooth circlular muscle
outer smooth longitudinal muscle
muscle tissue functions
structural/functional importance
mostly smooth/involuntary muscle with exceptions
functions by coordinating contractions to increase SA:V and pushes food/mixes with digestive substances
what is a sphincter
a thickened ring of muscle located at juncture of gut segments that can preven food moving back
steps of digestion through organs
mouth (mechanical and chemical)
oesophagus (peristalsis(contractions move food)) (glands secrete)
stomach (enzymes released by epithelial) (chyme pass in duodenum)
liver (produces bile into duodenum)
pancreas (produces/releases pancreatic fluid into duodenum)
small intestine (large SA:V good nutrient absorbtion)
large intestine (reabsorbtiom of water/ions)
what are hormones
chemical messenger system that regilate many bodily functions
carrys msgs to target tissues
lock and key system with receptors
how do hormones travel
endocrine gland
blood vessel
goes past all not target cells
finds target cell
protein hormones
hydrophilic (cannot easiky diffuse through membrane)
rely on receptors in membrane
steriod hormones
hydrophobic (can diffuse easily )
receptors for those inside nucleus/cytosol
what do endocrine glands do
release hormones directly into bloodstream
differ from exocrine and exo release into ducts
what is pituitary gland
pea sized gland at base of brain below the hypothalamus with an anterior and posterior
made of surface and nerve tissue
function of pituitary gland
stimulated to release hormones (stimulating/inhibiting)
links to other glands to turn on or off
target destination for many hormones
anterior pituitary
targets tissues include endocrine glands/body organs
made of glandular epithelial cells
front
posterior pituitary gland
told what to do by hypothalamus
target tissues include kidney/uterus
neurosectrtary cells
secrete into brain (oxytocin/antidiuretic)
hormone regulation
levels must be regulated
imbalance causes issues/conditions
what is adrenal gland
paired endocrine glands located at top of kidney
composed of outer cortex and inner medulla
what is adrenal cortex
composed of glandular tissue
produces cortoid hormones (steroids)
what does adrenal cortex produce
aldesterone (regulates BP/salt/water balance)
cortisol (regulates blood sugar/recovery from stress response)
(androgens (precursors to sex hormones)
what is adrenal medulla
cromaffin cells that produce adrenaline/noradrenaline
rapidly release in stress (nerve impulses) (fight/flight)
what is the thyroid gland
located at neck (around trachea/below larynx)
subunits produce major thyroid hormones (T3/T4 (thyroxine)/calcitonin)
only area to absorb iodine
regulated bu hypthalamus/anterior pi
what thyroid gland do
T3/T4 have effect on most body systems
increase basal metabolic rate
-mobilise fat
-increase cardiac output
-increase blood flow
what is hypo
underproducing
what is hyper
overproducing
what is parathyroid gland
endocrine glands located in posterior of thyroid
produce parathyroid hormone
works in conjunction with thyroid producing hormone calcitonin to regulate calcium
what is homeostasis
the maintanance of an organisms internal environment within the normal range (slightly above or below the set point) to avoid death/disease using regulatory methods
what is the set point
the most optimal point for the body to be in within thay catagory
characteristics of nervous system in homeostasis
fast spd of msg
immediate spd of response
short duration of respond
electrical/chem (neurotransmitters) along nerves
diff between neevous and endocrine in homeostasis
the nervous system gives an immediate, short lasting response whereas the endocrine gives a long lasting response that takes a bit to do
characteristics of endocrine in homeostasis
slow spd msg
slow spd response
long duration of response
chem (hormones) through bloodstream
mechanisms of regulation can be represented how
stimulus response model
stimulus or feedback
receptor
CNS/endocrine
effector
response
repeat
what is the stimulus in homeostasis
an increase or decrease in level of internal variable
what are receptors homeostasis
structure detects change
sends msg to hypothalamus
what is CNS and endocrine homeostasis
evaluates change against set point
sends msg of actuon to effector
what is effector homeostasis
strcture adjusts to required correction
what is negative feedback
when response has completed goal, may do too much, which is noticed and feedback is presented to get back to set point (seesaw)
receptors in stimulus response of homeostasis
detects stimuli/transmits signals via sensiry neurons
many types like chemo and mechano
which feedback loop is in homeostasis
negative
positive feeback loop
further amplifies change in variable
opposite of homeostasis
rare