BIO120 UNIT 6

hypothalamus hormones

CRH, TRH, GHRH

anterior pituitary hormones

ACTH, TSH, GH, FSH, LH, PRL, MSH

posterior pituitary hormones

oxytocin, ADH

thyroid hormones

T3,T4, calcitonin

parathyroid hormones

PTH

adrenal medulla

epinephrine, norepinephrine

pancreas hormones

insulin (beta cells) and glucagon (alpha cells)

pineal gland hormones

melatonin

thymus hormones

thymosin

hypothalamus function

maintains homeostasis by regulating various bodily functions, like the anterior pituitary

anterior pituitary function

plays a crucial role in the endocrine system, producing and releasing several hormones that regulate various bodily functions, including growth, metabolism, reproduction, and stress response

posterior pituitary function

primarily functions as a storage and release site for oxytocin (uterine contractions) and vasopressin (water retention)

thyroid function

responsible for regulating metabolism, growth, development and lowers blood calcium

parathyroid function

maintains blood calcium levels by raising it by using osteoclast activity

adrenal medulla function

plays a role in maintaining fight or flight

pancreas function

regulates blood sugar (glucose) levels

pineal gland function

plays a crucial role in regulating circadian rhythms (sleep wake cycles)

thymus gland

produces and trains T cells which are crucial for the body’s immune response

beta blockers

a class of medications that primarily work by blocking the effects of adrenaline and noradrenaline (epinephrine and norepinephrine) on the body, lowers blood pressure

sheehan’s syndrome

a rare condition where the pituitary gland is damaged due to severe blood loss (postpartum hemorrhage) during or after childbirth

hyperthyroidism

when the thyroid gland produces too much thyroid hormones, can lead to weight loss despite increased appetite, rapid or irregular heartbeat, tremors, nervousness, heat intolerance, and increased sweating

hypothyroidism

when your thyroid doesn’t make and release enough hormone, can lead to fatigue, weight gain, and increased sensitivity to cold

sympathetic nervous system

in charge of the “fight or flight” response, does this by triggering physiological changes like increased heart rate, breathing rate, and blood pressure to enable quick reactions to perceived threats or stressful situations

parasympathetic nervous system

responsible for the "rest and digest" response, promoting relaxation and energy conservation, does this by slowing heart rate, increasing digestive activity, and constricting pupils

somatic nervous system

responsible for voluntary control of body movements via skeletal muscles

preganglionic neurons

the first neurons in the autonomic nervous system (ANS) pathway, myelinated and originates in the central nervous system

postganglionic neurons

second neurons in the two-neuron chain of the autonomic nervous system, unmyelinated and extends to effectors

ganglia

clusters of neuron cell bodies located outside the central nervous system that contain postganglionic neuron cell bodies

acetylcholine

a neurotransmitter, a chemical messenger that transmits signals between nerve cells (neurons) and other cells in the body

• Released by all preganglionic neurons (sympathetic and parasympathetic).

• Also released by parasympathetic postganglionic neurons.
  

norepinephrine

a hormone and neurotransmitter that plays a crucial role in the body's "fight-or-flight" response

• Released by sympathetic postganglionic neurons

nicotinic receptors

ligand-gated ion channel that bind the neurotransmitter acetylcholine

• on postganglionic neurons

muscarinic receptors

a type of G protein-coupled receptor (GPCR) that primarily bind to acetylcholine

• on effector tissues

adrenergic receptors

proteins on cell surfaces that respond to the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline)

• on effector tissues

sympathetic outflow

the rate of nerve impulses transmitted from the sympathetic nervous system to target tissues, resulting in the release of neurotransmitters, primarily norepinephrine, that affect bodily functions

• thoracolumnar (T1-L2)

• short preganglionic, long postganglionic

parasympathetic outflow

the part of the autonomic nervous system that controls bodily functions during rest and digest

• craniosacral (brainstem, S2-S4)

• long preganglionic, short postganglionic.

splanchnic nerves

a group of autonomic nerves that primarily carry sympathetic fibers to the abdominal and pelvic organs

• preganglionic fibers synapse in collateral ganglia (not sympathetic chain ganglia)

carries parasympathetic fibers

cranial nerves 3,7,9,10

sympathetic effects on organs

heart rate and glucose goes up, pupils dilate, and blood travels to skeletal muscles

parasympathetic effects on organs

digestion, salvation, urination, and defecation increases and pupils constrict

innervate

supply (an organ or other body part) with nerves

hypothalamus

controls your autonomic nervous system and endocrine system

brainstem

houses the cranial parasympathetic outflow, specifically within the nuclei of cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus)

spinal cord (T1-L2)

sympathetic preganglionic neuron origin, these neurons send their axons out of the spinal cord through the ventral roots and then either synapse in sympathetic ganglia or in the adrenal medulla

where preganglionic axon terminals synapse

autonomic ganglia

where postganglionic axon terminals synapse

effector organs

water soluble hormone pathway

Hormone binds receptor on plasma membrane → G-protein → Adenylate cyclase → cAMP (second messenger) → Protein kinase → Cellular response (fast, brief duration)

lipid soluble hormone pathway

Hormone passes through plasma membrane → binds receptor in cytoplasm or nucleus → changes gene expression (transcription) in nucleus → Cellular response (slow, long-lasting)

negative feedback

a system where the output of a process or mechanism is fed back to reduce fluctuations in the output

• inhibits further hormone release

positive feedback

a mechanism where a change in a physiological variable triggers a response that further amplifies the initial change, moving the system away from its initial set point

• enhances response

anterior pituitary

hormones (GH, etc.) released in response to hypothalamic hormones in hypothalamohypophyseal portal (blood vessels); capillaries release hormones.

posterior pituitary

h rmones (ADH or oxytocin) released in response to hypothalamic nerve impulses in the hypothalamohypophyseal tract.