Topic 18 - Endocrine System Flashcards
Overview of the Endocrine System
- ductless glands and endocrine tissues within other organs
- secrete chemicals = hormones into blood
- transported to target cells via circulation and act on target cells
- target cell = cell with receptor specific for that hormone
Hormone Classes
List the classes of hormones
- Steroids
- Hormones derived from amino acids
- Peptide + Protein hormones
Hormone Classes
Steroids
- synthesized from cholesterol (lipid soluble)
- testosterone, estrogen, vitamin D
Hormone Classes
Hormones derived from amino acids
give example
and what kinds
- e.g. derived from tyrosine
2 kinds
- thyroxine/T4
- epinephrine + norepinephrine (catecholamines)
Hormone Classes ►Hormones derived from amino acids
Thyroxine/T4
what kind of hormone is it?
water or lipid soluble?
what does it do?
- a thyroid hormone
- lipid soluble
- controls cellular metabolism
Hormone Classes ►Hormones derived from amino acids
epinephrine + norepinephrine (catecholamines)
what kind of hormone is it?
water or lipid soluble?
what does it do?
- adrenal medulla hormones
- water soluble
- short term stress – part of the fight-or-flight response
Hormone classes
Peptide + Protein hormones
what is it?
water or lipid soluble?
name examples of these hormones
- chains of amino acids
- mainly water soluble
- e.g. oxytocin, antidiuretic hormone (ADH), growth hormone (GH), insulin
Endocrine Glands
Name the types of glands
these glands have __ _____ ________.
Glands with no other function:
- Pituitary gland
- Thyroid gland
- Parathyroid gland
- Adrenal gland
Endocrine Glands
Pituitary gland
how is it anatomically and functionally related to the _______.
where is it located?
how many lobes?
- suspended from hypothalamus
- in sella turcica of sphenoid bone
- 2 lobes
Endocrine glands ► Pituitary gland
what are the 2 lobes of the pituitary gland?
- Anterior pituitary
- Posterior pituitary
Endocrine gland ► Pituitary gland
Anterior pituitary
- what kind of tissue?
- how is it regulated?
- how many hormones?
- epithelial tissue
- anterior pituitary hormone secretion regulated by hormones released by the hypothalamus
- 3 metabolism hormones
- 3 reproductive hormones
Endocrine gland ► Pituitary gland ► Anterior pituitary
What are 3 metabolism hormones of the anterior pituitary?
- Growth hormone
- Thyroid stimulating hormone (TSH)
- Adrenocorticotropic Hormone (ACTH)
Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormone
Growth hormone
what does it stimulate or promote?
promotes growth or metabolism
Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormones
Thyroid stimulating hormone (TSH)
what does it stimulate or promote?
stimulates secretion of thyroid
Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormone
Adrenocorticotropic Hormone (ACTH)
stimulates secretion of adrenal steroids
Endocrine gland ► Pituitary gland ► Anterior pituitary
Name the reproductive hormones of the anterior pituitary
- Leutinizing Hormone (LH)
- Follicle Stimulating Hormone (FSH)
- Prolactin (PRL)
- stimulates milk formation
Endocrine gland ► Pituitary gland
Posterior pituitary
what kind of tissue?
how is it anatomically and functionally related to the ______?
how does the hypothalamus affect the pituitary gland?
- nervous tissue
- extension of hypothalamus
- hormones produced in hypothalamus, stored and secreted from the posterior pituitary:
- Oxytocin
- Antidiuretic Hormone (ADH)
Endocrine gland ► Pituitary gland ► Posterior pituitary
Oxytocin
what does it stimulate?
stimulates uterine contractions and milk ejection
Endocrine gland - Pituitary gland - Posterior pituitary
Antidiuretic Hormone (ADH)
water reabsorption in kidney
Endocrine gland
Thyroid gland
where is it located?
what is it composed of?
fact
- on anterior surface of the superior part of the trachea
- butterfly shaped
- Thyroid histology
- follicles
- parafollicular cells
Endocrine gland - Thyroid gland - Thyroid histology
Follicles
what are the walls composed of?
what does it produce?
- walls = epithelial cells (follicle cells)
- produce T4
Endocrine gland - Thyroid gland - Thyroid histology
Parafollicular cells
where is it located?
what does it secrete?
- between follicles
- secrete calcitonin
- increase Ca++ uptake into bone (bone formation) which lowers blood Ca++ bone matrix
Endocrine glands
Parathyroid glands
where is it located and how many?
what does it secrete?
- 4 (usually) glands embedded in posterior thyroid
- secrete parathyroid hormone (PTH)
- increase blood Ca++ by breaking down bone matrix
Endocrine glands
Adrenal glands
where is it located?
what are the 2 parts?
- superior surface of each kidney
- 2 parts
- adrenal cortex (outer)
- adrenal medulla (inner)
Endocrine glands - Adrenal glands
Adrenal cortex (outer)
what tissue?
what does it secrete?
how many layers?
- how many hormones are secreted by each layer?
- epithelial tissue
- secretes steroids only
- 3 layers (1 hormone secreted by each):
- Zona Glomerulosa
- Zona Fasciculata
- Zona reticularis
Endocrine glands - Adrenal glands - Adrenal cortex
Zona glomerulosa
what does it secrete?
secretes mineralcorticoids (mainly aldosterone)
- salt balance
Endocrine glands - Adrenal glands - Adrenal cortex
Zona fasciculata
what does it secrete?
- example
- what kind of hormone?
secretes glucocorticoids (e.g. cortisol)
- long term stress hormone
- carbohydrate metabolism
Endocrine glands - Adrenal glands - Adrenal cortex
Zona reticularis
what does it secrete?
secretes androgens + small amounts testosterone
- some converted to estrogens in other tissues (especially fat)
endocrine gland - adrenal gland
Adrenal medulla (inner)
what kind of tissue?
what hormones?
- nervous tissue
- 2 main hormones:
- epinephrine (80%)
- norepinephrine (20%)
Endocrine tissues
name the 4
Endocrine function in organs that have other functions as well:
- Pancreatic Islets of Langerhans
- Hypothalamus
- Gonads
- Others
Endocrine tissues
Pancreatic islets of langerhans
- 4 cell types (only covering 2 in this course)
- a-cells
- b-cells
a-cells
produce glucagon
-increases blood glucose
b-cells
produces insulin
-decreases blood glucose
Endocrine tissue
Hypothalamus
regulates anterior pituitary via:
- GHRH (growth hormone releasing hormone)
- GHIH (Growth hormone inhibiting hormone)
- HnRH (Gonadotropin releasing Hormone) - FSH + LH
Endocrine tissues
Gonads
- Testes
- leydig cells = testosterone
- Ovaries
- Cells of 1º and 2º follicles = estrogen
- corpus luteum = estrogen + progesterone
Endocrine Tissues
List the others
- duodenum - secretin
- kidney - renin
- skin - vitamin D
- heart - atrial natruiretic peptide (ANP)
- etc.
