anant exam 3 Flashcards
effectors of ANS
smooth muscle, cardiac muscle, glands
preganglionic neurons
- cell body in CNS, axons enter PNS
- axons contribute to cranial and spinal nerves
- lightly myelinated
- slow conduction velocity
- neurons are cholinergic (Ach)
postganglionic neurons
- neurons completely in PNS
- cell bodies form peripheral ganglia
- nonmyelinated
- very slow conduction velocity
- either cholinergic (Ach) or adrenergic (Epi or NEpi)
- axons synapse with effector organ
SYMPATHETIC preganglionic neurons
- cell body in thoracic and lumbar spinal cord ( T1-L1)
- short preganglionic axon
- ALL are cholinergic (Ach)
SYMPATHETIC postganglionic neurons
- cell bodies in sympathetic chain ganglia (paravertebral) or collateral (prevertebral) ganglion
- long postganglionic axons
- MOST are adrenergic (Epi or NEpi)
somatic vs autonomic nervous sytem
somatic: effectors are skeletal muscles, motor neurons exert direct control over skeletal muscles.
autonomic: effectors are viscera, motor neurons synapse on visceral motor neurons in autonomic ganglia and ganglionic neurons control visceral effectors
sympathtic nervous system
(thoracolumbar) activated during fight or flight conditions, preganglionic fibers are short and post ganglionic fibers are long
sympathtic responces
- heightened mental alertness
- increased metabolic rate
- reduced digestive and urinary functions
- activation of energy reserves
- increased respiration & dilation to airways
- increased hr and bp
- sweat
parasympathetic nervous system
craniosacral, rest and digest, preganglioni fibers are long and post ganglionic fibers are short
parasympathetic responces
- decreased metabolic rate
- decreased HR and BP
- increased salivation and digestive secretions
- increased blood flow in digestive system
- stim of urination and defection
sympathetic chain ganglia
located on both sides of the vertebral column, control effectors in the body wall, inside thoracic cavity, and in head & limbs
collateral ganglia
anterior to vertebral bodies, contain ganglionic neurons that innervate tissues and organs in the abdominopelvic cavity
adrenal medullae
modified sympathetic ganglion, have very short axans
where are preganglionic sympathtic fibers found?
ventral roots of spinal segments T1-L2
innervation of adrenal medullae
secretes E and NE, preganglionic fibers innervate directly
cholinergic receptors
synapses that use Ach as a transmitter, effect is always excitatory, most are preganglionic
adrenergic
neurons release NE, most are sympathetic ganglionic.
alpha receptors
activates enzymes on the inside of the plasma membrane, more common, adrenergic
beta receptors
located on plasma membranes of cells of many organs, adrenergic
nicotinic receptors
cholinergic receptor, at neuromuscular junctions, opens chemically gated channels, PARASYMP
muscarinic
g proteins, can be excitatory or inhibitory, changes K membrane permeability, occurs at all nuromuscular or neuroglandular junctions, PARASYMP
preganglionic PARASYMPATHETIC neurons occur in….
- midbrain, pons, and medulla.
- associated with cranial nerves III, VII, IX, X
- in lateral gray horns of S2-S4
parasympathetic stimulation is specific/ localized and long lasting. (t/f)
FALSE. they are localized but last BRIEFLY
what nerves do parasympathetic leave the brain in?
III, VII, IX, X, also in s2-s4
wha neurotransmitter do sympathetic neurons release?
preganglionic: Ach
postganglionic: mostly NE but some release Ach or NO
what neurotransmitters do parasympathetic neurons release?
always releases Ach
dual innervation
some vital organs recieve both sympathetic and parasympathetic innervation
parasympathetic ganglionic neurons are located ___ their target organs
within or next to
the vagus nerve provides 75percent of parasymp outflow. (t/f)
true
sympathetic division contains __ set(s) of chain ganglia
2
how many collateral ganglia does the sympathetic division have?
3
exocrine gland
a gland that secretes onto epithelial surfaces or into a duct connected to the exterior
endocrine gland
a gland that secretes secretions into extracellular fluid
direct communication
occurs between two cells, transports ions through gap junctions, limited yo adjacent cells
paracrine communication
transports paracrine factors through extracellular fluid, limited to a local area
endocrine communication
transmits hormones through the bloodstream, extends to other tissues of the body
synaptic communication
transmits neurotransmitters across synaptic cleft, good for emergency situations, limited to very specific area
ways the endocrine and nervous system maintain homeostasis
- both rely on chemical s that bind to specific receptors
- both share many chemical messengers
- both are regulated by NEGATIVE FEEDBACK
- both coordinate and regulate activities of other cells and areas
Eicosanoids are __ soluable
lipid
catecholamines are ___ soluable
water
peptide hormones are ___ soluable
water
lipid soluble hormones include
sterioid hormones, thyroid hormones, and gas
water soluble hormones include
amines, peptides and proteins
lipid soluble proteins do not need transport protein in blood capillaries (t/f)
FALSE. they do need a transport protein in capillaries
intracellular receptors
lipid soluble proteins
extracellular receptors
water soluble proteins. need receptor and g protein
parts of anterior pituitary
pars tuberalis, pars distalis, pars intermedia
*has rich blood supply
hormones of the anterior pituitary
- Thyroid stimulating hormone (TSH)
- adrenocorticotropic hormone (ACTH)
- follicle stimuating hormone (FSH)
- luteinizing hormone (LH)
- prolactin (PRL)
- growth hormone (GH)
pars intermedia secretes
melanocyte stimulating hormone
thyroid stimulating hormone (TSH)
triggers the release of thyroid hormones and iodide transport into follicle cells. released in response to TRH.
adrenocorticotropic hormone (ACTH)
triggers the release of glucocorticoids in the adrenal cortex
follicle stimulating hormone (FSH)
promotes follicle development in ovaries and triggers estrogen secretion
luteinizing hormone (LH)
induces ovulation, secretion of progesterone
prolactin (PRL)
stimulate mammary gland development and production of milk
growth hormone (GH)
growth, protein synthesis, lipid mobilization, and catabolism
melanocyte stimulating hormone (MSH)
increased melanin synthesis in epidermis
hormones of the posterior pituitary
antiduretic hormone (ADH) and oxytocin (OXT)
antidiuretic hormone (ADH)
reabsorption of water at kidneys, inceased BP and blood volume in response to dehydration, elevated BP and BV
oxytocin (OXT)
labor contractions and milk ejection in females in response to uterine distension and nipple stim
why is the hypothalamus considered an endocrine gland?
- secretes regulatory hormones
- releases hormones at posterior pituitary
- excerting neural control over cells in adrenal medulla
location of the thyroid gland
inferior to larynx
*rich blood supply, simple cuboidal cell compose follicle
thyroid follicle cells synthesize and secrete __?
thyoglobulin
what amino acid is the building block of thyroid hormone?
tyrosine
main thyroid hormones are __?
T4 and T3 (triodothyronine)
functions of thyroid hormones
- increase rates of metabolism
- bind to cytoplasm
- activation of a specific gene
- specific transport to target cell
C cells of the thyroid
produce calcitonin (CT), respond directly to elevated Ca concentration in the blood
calcitonin (CT)
inhibits osteoclasts which slows the rate of Ca release from the bone, and triggers Ca release from the kidneys, decrease blood Ca levels!
effects of thyroid hormones on tissues
- elevates rates of oxtgen and energy consumption
- increases HR and force of contraction
- increases sensitivity to symp stimulation
- maintains sensitivity of respiratory centers to change in gases
- stimulates RBC formation
- stims other endocrine activity
- accels mineral turnover in bone
parathyroid gland location
2 pairs embedded in posterior surfaces of thyroid gland
parathyroid chief cells secrete __?
parathyroid hormone (PTH), stimulated by low calcium levels in blood
parathyroid hormone (PTH)
increase Ca concentrations in bodily fluids:
- inhibits osteoblasts and increases osteoclast numbers which reduces calcium deposition in bone
- enhances reabsorption of Ca by kidneys
- stimulates formation and secretion of calcitriol by kidneys
location of adrenal glands
superior to each kidney
adrenal cortex
stores corticosteroids, consists of outer zona glomerulosa, zona fasciculata, and inner zona reticullaris
zona glomerulosa
secretes mineralocorticoids, mainly aldosterone
aldosterone
secretion occurs in response to fall in blood Na content or rise in K. increases renal absorption of Na and water and loss of K
zona fasciculata
secretes glucocorticoids, mainly cortisol, regulated by negative feedback
effects of glucocorticoids
- anti inflammatory effects
- speed up rates of glucose synthesis
- release of fatty acids into the blood
zona reticularis
secretes androgens
androgens
bone growth, muscle growth, blood formation
adrenal medulla
innermost part of the adrenal gland, secretes epinephrine and norepinephrine
epinephrine and norepinephrine
releases lipids, increases HR, BP, blood glucose, stimulated during symp activation
location of the pancreas
between inferior border of the stomach and proximal portion of small intestine
exocrine pancreas
consists of pancreatic acini and attached ducts, takes up majority of the pancreas
endocrine pancreas
small groups of pancreatic islets (langerhans!)
alpha cells of the pancreas
produce glucagon
glucagon
raises blood glucose by increasing glycogen breakdown and glucose release
beta cells
produce insulin
insulin
lowers blood glucose levels by increasing rate of glucose uptake and utilization and glycogen synthesis in skeletal muscles and liver
type 1 diabetes
destruction of beta cells, insulin dependent
type 2 diabetes
insulin is made normally, the body just can’t respond to it properly.
