Part 8: Endocrine system Flashcards
label: endocrine glands & tissues
blue: pituitary gland
yellow: thyroid gland
red: adrenal gland
green: pineal gland
black: parathyroid glands
grey: thymus
orange: pancreas
purple: gonads
pink :tissues : digestive tract, kidneys, heart, adipose tissue
endocrine system is a collection of _____ that secrete ____ into _____
glands and tissues of the body
chemical messengers (hormones)
blood, directly or via interstitial fluid or lymph.
endocrine system integrates _______
the activities of organs and organ systems throughout the body
______function together to maintain homeostasis
nervous and endocrine systems
glands (def.)
Glandular epithelium consists of specialized cells that synthesize, store, and secrete chemical substances
Two types of glands
1) exocrine: release secretions onto epithelial surface through ducts
2) endocrine: release secretions into blood (directly or via interstitial fluid)
examples of exocrine glands
sweat, mammary, salivary
examples of endocrine glands
thyroid, pituitary, adrenal (suparenal)
hormone is a _____ that : (3 things)
chemical messenger
-is produced and secreted by an endocrine cell
-travels through the circulatory system to reach other tissues
-acts upon specific target cells within the tissue
nervous system vs endocrine system
-signal sent by neurons vs signals sent by endocrine glandular cells
-signals are electrical impulses vs signals are hormones
-highly specific vs widespread
-short term activity vs long duration
_____ modify secretion from endocrine glands and _____ modify CNS function
brain
hormones
similarities between neurons and gland cells
-both secret chemical messenger on target cell
-same molecule can be neurotransmitter and hormone (adrenaline and vasopressin)
-some neurons release directly in blood/hormones
types of hormones
-amino acid derivatives (ex. adrenaline)
-peptide hormones (ex. oxytocin- coded by gene)
-steroid hormones (ex. estrogen - from cholesterol backbone)
-eicosanoid hormones (least common)-local signals
Thyroid hormones do what? important for?
-elevate cellular oxygen and metabolic rate
-important for growth and development
Thyroid gland location
-anterior to trachea, just inferior to the larynx/ thyroid cartilage
-anchored to first 2-3 tracheal rings
thyroid gland (descr.)
butterfly shape; right and left lobes joined by an isthmus
has large blood supply
thyroid is made of ____ and are surrounded by _____. In the middle of a follicle, there is _____
thyroid follicles
follicular cells (T thyrocytes) - has large nucleus
colloid = viscous protein-rich fluid inside follicles
T thyrocytes do what?
-produce a large protein, thyroglobulin (Tg), and store it in the lumen of the follicle.
-pump iodine into the lumen, and enzymes on their luminal surface will add iodine to the Tg.
thyroglobulin is the precursor for _____
thyroid hormone
Thyroid stimulating hormone (TSH) induces _____
thyrocytes to remove Tg from the lumen, cleave off T3, T4, and release them into the blood
Thyroid hormones are derivatives of the amino acid ______, with _____added.
tyrosine
iodine
The thyroid releases mainly ______, but ______ is the more active form. Peripheral tissues can convert _____. Both regulate metabolism.
thyroxine (T4)
triiodothyronine (T3)
T4 to T3
T4 has how many iodine molecules? T3 has how many iodine molecules?
-4
-3
hypothyroidism (def.) + symptoms
-too little thyroid hormones
-weight gain, fatigue, depression
hyperthyroidism (def.) + symptoms
-too much thyroid hormones
-weight loss, anxiety, difficulty sleeping, irregular heartbeat
______act as master regulators of endocrine system.
Hypothalamus and pituitary
regulation of thyroid function by hypothalamus + pituitary
hypothalamus releases TRH (thyroid releasing hormone) causing pituitary to release TSH (thyroid stimulating hormone) –> release of T4 and T3 b thyroid
feed back loop of thyroid function
T4, T3 from thyroid –> negative feedback to pituitary and hypothalamus = decrease TSH from pituitary and TRH from hypothalamus
Pituitary Gland (aka _____)
Hypophysis cerebri
pituitary glans sits where?
sella turcica (“bony saddle”)
pituitary gland is connected to brain via ______
pituitary stalk (infundibulum)
Label pituitary gland
- red: Infundibulum (pituitary stalk)
-blue: Anterior lobe (Adenohypophysis) -look like a gland, has cuboidal epithelial cells
-orange: Posterior lobe (Neurohypophysis) - has nerve terminals (axons)
Hypothalamic-Hypophyseal Portal System (DEF.) + label
a system of blood vessels that connects the hypothalamus and the anterior pituitary gland
blue: Neurosecretory cells in hypothalamus
red: Superior hypophyseal artery
yellow: Primary capillary plexus
green: Portal veins
purple: Secondary capillary plexus
black: Efferent veins
portal veins connect ___
two capillary beds
primary capillary plexus of portal system receives _____
neurotransmitters (now hormones since it’s secreted in blood) from hypothalamus –> carries it to secondary plexus in anterior pituitary
Anterior Pituitary Hormones
Human Growth Hormone (hGH)
Thyroid Stimulating Hormone (TSH)
Follicle Stimulating Hormone (FSH)
Luteininzing Hormone (LH)
Prolactin (Prl)
Adrenocorticotropic Hormone (ACTH)
Melanocyte Stimulating Hormone (MSH)
Thyroid Stimulating Hormone (TSH) does what? Adrenocorticotropic Hormone (ACTH)? Follicle Stimulating Hormone (FSH)?
Luteininzing Hormone (LH)?
Prolactin (Prl)?
Human Growth Hormone (hGH)?
Melanocyte Stimulating Hormone (MSH)?
-stimulates production of T3, T4
-stimulates production of glucocorticoid
-follicle development and estrogen secretion, sperm maturation
-ovulation, progesterone, testersterone secretion
-milk production
- growth
-melanin production
label neurohypophysis
blue: Neurosecretory cells of supraoptic nucleus
red: Neurosecretory cells of paraventricular nucleus
green: Hypothalamohypophyseal tract
purple: Inferior hypophyseal artery
yellow: Capillary plexus of neurohypophysis
black: Efferent veins
Posterior Pituitary Hormones
Vasopressin aka Antidiuretic Hormone (ADH)
Oxytocin
Vasopressin (ADH) function + made by ____
regulates concentration of urine
functions in the regulation of blood pressure
made by neurons of supraoptic nucleus in posterior pituitary
Oxytocin function + made by ____
stimulates uterine muscle contraction during childbirth
stimulates release of milk from mammary glands (letdown)
made by neurons of paraventricular nucleus
label Hypothalamic-Pituitary-Adrenal Axis
blue: corticotropin-releasing hormone (CRH)
red: adrenocorticotropic hormone (ACTH)
Adrenal (______) Glands
Suprarenal
on top of the kidney
label adrenal gland
red: cortex
blue: medulla
The cortex of adrenal gland stores ______
cholesterol and fatty acids to use in the synthesis of >24 steroid hormones (corticosteroids)
label layers of adrenal cortex
red: zona glomerulosa
blue: zona fasciculata
green: zona reticularis
yellow: medulla
zona fasciculata of cortex creates _____ after stimulation by _____
Glucocorticoids (ex. cortisol)
ACTH
cortisol function
-control a number of physiological functions for both resting homeostasis and in response to stress (e.g. glucose metabolism)
-used for immunosuppressive and anti-inflammatory properties
zona glomerulosa of cortex creates _____ (ex. _____), which does what?
Mineralocorticoids
aldosterone
controls electrolyte balance
Increases renal absorption of Na+ and H2O
Decreases renal absorption of K+
zona reticularis of cortex creates _____ (ex. _____), which does what?
Androgens
Sex hormones
Stimulates growth of axillary and pubic hair
Important source of androgens in adult females
Chromaffin Cells of Adrenal Medulla are ______ and are equivalent to _______
Neuroendocrine cells
post-ganglionic sympathetic neurons
Chromaffin Cells of Adrenal Medulla releases ____ for _____
Release adrenaline/noradrenaline (epinephrine/norepinephrine) into blood
Fast response to stress
Hormones of the Adrenal Medulla
Epinephrine and Norepinephrine
Epinephrine and Norepinephrine function
Fight or flight response
Increase cardiac output
Increase blood pressure
Increase blood glucose
Effect release of lipids from adipose tissue
But not all organs are under direct hypothalamic/pituitary control (ex. ______)
pancreas (self regulating)- mostly exocrine function
label internal structure of pancreas
blue: exocrine pancreas
red: capillaries
black: islet of langehans- endocrine function
islet of langehans label + secretion
blue : alpha cell secretes glucagon (increase glucose- acts on liver)
yellow: beta cell secretes insulin (decrease glucose- acts on body cells
purple: delta cell secretes somatostatin (inhibits secretion of glucagon and insulin)
Diabetes Mellitus (def.) + sympotoms
Inability to produce or use insulin
Elevation of blood glucose levels (hyperglycemia)
Excretion of glucose in urine
types of diabetes mellitus
Two types
Type I – 10%- autoimmune disease –> attacks B-cells
Type II – 90%
Type I Diabetes (called _____) summary
-Autoimmune disease that destroys insulin-secreting cells of islets
-Marked reduction of insulin levels
-Called insulin-dependent diabetes
-Can occur at any age but is more common between ages 5 – 20
Type II Diabetes (called _____) summary
-Combination of insulin-resistance and insulin-secretory defects
-Target cells become less sensitive to insulin
-Due to down-regulation of receptors
-Called non-insulin-dependent diabetes
-Correlates with age and obesity
-Initial management by diet, exercise and weight loss
Other Endocrine Glands
Parathyroid glands
Gonads
Pineal gland
Thymus gland
Parathyroid hormone produced by _____ that are where? functions?
parathyroid glands
sit posterior to thyroid gland
Increases Ca2+ in body fluids
Decreases Ca2+ deposition in bone
Calcitonin produced by _____ that are where? functions?
produced by C-cells that reside in the thyroid (separate from thyroid function)
Decreases Ca2+ in body fluids
Increases Ca2+ deposition in bone
_____is ____ that secretes ____ and regulates ______
Pineal Gland
Small midline structure at the posterior end of the 3rd ventricle
Secretes melatonin
Regulates biological clock
Thymus Gland secretes ______ which promotes _____
thymic hormones
proliferation and maturation of T-lymphocytes
Gastrointestinal Tract produces ____different hormones that regulate activity of _____
20
GI tract and digestive glands
Kidneys produces ____ which increases _____ and ____ which increases _____
Erythropoietin - increases RBC production
Renin - increases blood pressure
Heart secretes ____ which decreases ____
Atrial Natriuretic peptide
Decreases blood pressure
Adipose tissue secretes ____ which are _____
Leptins
Appetite suppressant
