Chapter 45: Endocrine System. Learning Targets 1. I can idnetify and explain the role that hormones...
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Transcript of Chapter 45: Endocrine System. Learning Targets 1. I can idnetify and explain the role that hormones...
Learning Targets
1. I can idnetify and explain the role that hormones have in homeostatic pathways. I can diagram how hormones bind to tarfet receptors and trigger
specific pathways. I can explain one hormone that displays positive feedback and one
that displays negative feedback.
2. I can explain how steriod and peptide hormones differ as ligands in signal transduction pathways.
3. I can explain the significance of having antagonistic hormones to maintain homeostasis.
Figure 45.21
Spinal cord(cross section)
(a) (b) Long-term stress responseand the adrenal cortex
Short-term stress responseand the adrenal medulla
Stress
Nervesignals
Nervecell
Releasinghormone
Hypothalamus
Anterior pituitary
Blood vessel
Nerve cell ACTHAdrenal medullasecretes epinephrineand norepinephrine.
Adrenalgland
Kidney
Adrenal cortexsecretes mineralo-corticoids andglucocorticoids.
Effects of epinephrine and norepinephrine: Effects of mineralocorticoids:
Effects of glucocorticoids:
• Glycogen broken down to glucose; increased blood glucose
• Increased blood pressure • Increased breathing rate• Increased metabolic rate• Change in blood flow patterns, leading to
increased alertness and decreased digestive,excretory, and reproductive system activity
• Retention of sodium ions and water by kidneys
• Increased blood volume and blood pressure
• Proteins and fats broken down and converted to glucose, leading to increased blood glucose
• Partial suppression of immune system
Figure 45.7-2
Epinephrine
G protein
Adenylylcyclase
G protein-coupledreceptor
GTP
ATP
cAMP Secondmessenger
Inhibition ofglycogen synthesis
Promotion ofglycogen breakdown
Proteinkinase A
Figure 45.9 Different receptorsSame receptors but differentintracellular proteins (not shown)
Different cellularresponses
Different cellularresponses
Epinephrine Epinephrine Epinephrine
receptor receptor receptor
Glycogendeposits
Vesseldilates.
Vesselconstricts.
Glycogenbreaks downand glucoseis releasedfrom cell.
(a) Liver cell (b) Skeletal muscleblood vessel
Intestinal bloodvessel
(c)
Figure 45.11Pathway Example
Stimulus Low pH in
duodenum
Endocrinecell
S cells of duodenumsecrete the hormonesecretin ( ).
Hormone
Bloodvessel
Targetcells
Pancreas
Response Bicarbonate release
Neg
ativ
e fe
edb
ack
Figure 45.12Pathway
Example
Stimulus Suckling
Sensoryneuron
Po
siti
ve f
eed
bac
k
Hypothalamus/posterior pituitary
Neurosecretory cell
Neurohormone
Blood vessel
Targetcells
Response
Posterior pituitarysecretes theneurohormoneoxytocin ( ).
Smooth muscle inbreasts
Milk release
Figure 45.16
Tropic effects only:FSHLHTSHACTH
Nontropic effects only:ProlactinMSH
Nontropic and tropic effects:GH Hypothalamic
releasing andinhibitinghormones
Posteriorpituitary
Neurosecretorycells of thehypothalamus
Portal vessels
Endocrine cellsof the anteriorpituitary
Pituitaryhormones
HORMONE FSH and LH TSH ACTH Prolactin MSH GH
TARGET Thyroid MelanocytesTestes orovaries
Adrenalcortex
Mammaryglands
Liver, bones,other tissues