Download Regulation and Control

Regulation and Control
• Endocrine System-is a series of hormoneproducing glands throughout the body which
are circulated through the blood and influence
target cells
AP-Pertinent Endocrine Info
• Posterior Pituitary-stores ADH (antidiuretic hormone)
and oxytocin, which are produced in the hypothalamus
• Anterior Pituitary-produces tropic hormones
(hormones that target other glands)
– Regulated by releasing hormones produced by the
hypothalamus
• Pancreas
– Islets of Langerhans have 2 cell types (producing antagonistic
hormones)
• Alpha cells-secrete glucagon into the blood when blood sugar
drops, stimulating the liver to release glucose
• Beta cells-secrete insulin, stimulating the liver to take up
glucose and convert it to glycogen or fat
Figure 47-3-1
Hypothalamus
Growth-hormone-releasing hormone:
stimulates release of GH from pituitary
gland
Corticotropin-releasing hormone (CRH):
stimulates release of ACTH from pituitary
gland
Thyroid-releasing hormone: stimulates
release of TSH from thyroid gland
Gonadotropin-releasing hormone:
stimulates release of FSH and LH from
pituitary gland
Antidiuretic hormone (ADH): promotes
reabsorption of H2O by kidneys
Oxytocin: induces labor and milk release
from mammary glands in females
Polypeptides
Amino acid derivatives
Steroids
Figure 47-3-2
Polypeptides
Amino acid derivatives
Steroids
Thyroid gland
Thyroxine: increases metabolic rate
and heart rate; promotes growth
Adrenal glands
Epinephrine: produces many effects
related to short-term stress response
Cortisol: produces many effects related to
short-term and long-term stress responses
Aldosterone: increases reabsorption of
Na+ by kidneys
Kidneys
Erythropoietin (EPO): increases
synthesis of red blood cells
Vitamin D: decreases blood Ca2+
Testes (in males)
Testosterone: regulates development
and maintenance of secondary sex
characteristics in males; other effects
Figure 47-3-3
Polypeptides
Amino acid derivatives
Steroids
Pituitary gland
Growth hormone (GH): stimulates
growth
Adrenocorticotropic hormone (ACTH):
stimulates adrenal glands to secrete
glucocorticoids
Thyroid-stimulating hormone (TSH):
stimulates thyroid gland to secrete
thyroxine
Follicle-stimulating hormone (FSH)
and luteinizing hormone (LH): involved
in production of sex hormones;
regulate menstrual cycle in females
Prolactin: stimulates mammary gland
growth and milk production in females
Figure 47-3-4
Polypeptides
Amino acid derivatives
Steroids
Parathyroid glands
Parathyroid hormone (PTH):
increases blood Ca2+
Pancreas (islets of Langerhans)
Insulin: decreases blood glucose
Glucagon: increases blood glucose
Ovaries (in females)
Estradiol: regulates development and
maintenance of secondary sex
characteristics in females; other effects
Progesterone: prepares uterus for
pregnancy
Figure 47-16
The posterior pituitary
The anterior pituitary
Hypothalamus
Neurosecretory
cells of the
hypothalamus
Hypothalamic
hormones
Neurosecretory
cells of the
hypothalamus
Hypothalamic
hormones
Blood vessels
Posterior
pituitary
Anterior
pituitary
Blood vessels
Pituitary
hormones
Hormone
Target
Response
ADH
Oxytocin
Kidney
nephrons
Mammary glands,
uterine muscles
Aquaporins Contraction during
activated; H2O labor; ejection of
reabsorbed milk during nursing
Hormone
Target
Response
ACTH
Adrenal
cortex
Follicle-stimulating Growth
hormone (FSH) hormone
and luteinizing
(GH)
hormone (LH)
Testes or
ovaries
Prolactin
(PRL)
Many tissues Mammary
glands
Thyroidstimulating
hormone
(TSH)
Thyroid
Production of Production of sex Growth
Mammary
Production of
glucocorticoids hormones; control
gland growth;
thyroid
of menstrual cycle
milk production
hormones
How hormones work
• Method 1: (for steroid hormones)
– The hormone diffuses through the pm and heads for the
nucleus.
– It binds to a receptor protein in the nucleus, which activates
the DNA to turn on a specific gene
• Method 2: (for protein hormones)
– The hormone binds to a receptor on the plasma membrane
(receptor-mediated endocytosis), which stimulates a second
messenger
– 2nd messengers can be cAMP, which triggers an enzyme that
makes cellular changes, or Inositol triphosphate (IP3) that
triggers the release of calcium ion from the ER, that triggers
enzymes to make cellular changes
Figure 47-18
STEROID HORMONE ACTION
Nucleus
Hormone
receptor
Steroid
hormone
mRNA
Proteins
DNA
Hormonereceptor
complex
1. Steroid
2. Hormone binds
hormone
enters
target cell.
to receptor, induces
conformational
change.
Hormoneresponse
element
RNA
polymerase
3. Hormone-receptor
4. Many mRNA
complex enters
nucleus and binds
to DNA, induces
start of transcription.
transcripts are
produced,
amplifying
the signal.
Ribosome
5. Each transcript is
translated many times,
further amplifying the
signal.
Figure 47-21
MODEL FOR EPINEPHRINE ACTION
1. Epinephrine
binds to receptor
Epinephrine
Adenylyl
cyclase
Receptor
2. Activation
of G protein
3. Activated
adenylyl cyclase
catalyzes
formation of
cAMP
Transmission of
message from
cell surface
4. Activation of cAMP-dependent protein
kinase A
5. Activation of phosphorylase kinase
6. Activation of phosphorylase
7. Production of glucose from glycogen
Feedback Loops
• Positive
– Increases an already present response.
– “good job, keep going”
– Oxytocin during labor increases contractions. As the
baby’s head presses on the uterus the oxytocin
increases.
• Negative
– Maintains balance by turning off a hormone when it is
no longer needed.
– High levels of thyroxin “turn off” the hypothalamus
and pituitary glands. They “turn on” when levels are
low.
Endocrine Disorders and
Environmental Effects
•Gigantism
•Infertility Issues
•Goiter
•Hyper-/ Hypothyroidism
•Diabetes
•Hormones in modified foods can affect the immune
system.
•BPA found in plastics reacts in the body like estrogen.