Topic 18 - Endocrine System

Question 1

Overview of the Endocrine System

Answer 1

• 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

Question 2

Hormone Classes

List the classes of hormones

Answer 2

1. Steroids
2. Hormones derived from amino acids
3. Peptide + Protein hormones

Question 3

Hormone Classes

Steroids

Answer 3

• synthesized from cholesterol (lipid soluble)
• testosterone, estrogen, vitamin D

Question 4

Hormone Classes

Hormones derived from amino acids

give example

and what kinds

Answer 4

• e.g. derived from tyrosine

2 kinds

1. thyroxine/T4
2. epinephrine + norepinephrine (catecholamines)

Question 5

Hormone Classes ►Hormones derived from amino acids

Thyroxine/T4

what kind of hormone is it?

water or lipid soluble?

what does it do?

Answer 5

• a thyroid hormone
• lipid soluble
• controls cellular metabolism

Question 6

Hormone Classes ►Hormones derived from amino acids

epinephrine + norepinephrine (catecholamines)

what kind of hormone is it?

water or lipid soluble?

what does it do?

Answer 6

• adrenal medulla hormones
• water soluble
• short term stress – part of the fight-or-flight response

Question 7

Hormone classes

Peptide + Protein hormones

what is it?

water or lipid soluble?

name examples of these hormones

Answer 7

• chains of amino acids
• mainly water soluble
• e.g. oxytocin, antidiuretic hormone (ADH), growth hormone (GH), insulin

Question 8

Endocrine Glands

Name the types of glands

these glands have __ _____ ________.

Answer 8

Glands with no other function:

1. Pituitary gland
2. Thyroid gland
3. Parathyroid gland
4. Adrenal gland

Question 9

Endocrine Glands

Pituitary gland

how is it anatomically and functionally related to the _______.

where is it located?

how many lobes?

Answer 9

• suspended from hypothalamus
• in sella turcica of sphenoid bone
• 2 lobes

Question 10

Endocrine glands ► Pituitary gland

what are the 2 lobes of the pituitary gland?

Answer 10

1. Anterior pituitary
2. Posterior pituitary

Question 11

Endocrine gland ► Pituitary gland

Anterior pituitary

• what kind of tissue?
• how is it regulated?
• how many hormones?

Answer 11

• epithelial tissue
• anterior pituitary hormone secretion regulated by hormones released by the hypothalamus
• 3 metabolism hormones
• 3 reproductive hormones

Question 12

Endocrine gland ► Pituitary gland ► Anterior pituitary

What are 3 metabolism hormones of the anterior pituitary?

Answer 12

1. Growth hormone
2. Thyroid stimulating hormone (TSH)
3. Adrenocorticotropic Hormone (ACTH)

Question 13

Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormone

Growth hormone

what does it stimulate or promote?

Answer 13

promotes growth or metabolism

Question 14

Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormones

Thyroid stimulating hormone (TSH)

what does it stimulate or promote?

Answer 14

stimulates secretion of thyroid

Question 15

Endocrine gland ► Pituitary gland ► Anterior pituitary ► Metabolism hormone

Adrenocorticotropic Hormone (ACTH)

Answer 15

stimulates secretion of adrenal steroids

Question 16

Endocrine gland ► Pituitary gland ► Anterior pituitary

Name the reproductive hormones of the anterior pituitary

Answer 16

1. Leutinizing Hormone (LH)
2. Follicle Stimulating Hormone (FSH)
3. Prolactin (PRL)
   
   • stimulates milk formation

Question 17

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?

Answer 17

• nervous tissue
• extension of hypothalamus
• hormones produced in hypothalamus, stored and secreted from the posterior pituitary:
  
  • Oxytocin
  • Antidiuretic Hormone (ADH)

Question 18

Endocrine gland ► Pituitary gland ► Posterior pituitary

Oxytocin

what does it stimulate?

Answer 18

stimulates uterine contractions and milk ejection

Question 19

Endocrine gland - Pituitary gland - Posterior pituitary

Antidiuretic Hormone (ADH)

Answer 19

water reabsorption in kidney

Question 20

Endocrine gland

Thyroid gland

where is it located?

what is it composed of?

fact

Answer 20

• on anterior surface of the superior part of the trachea
• butterfly shaped
• Thyroid histology
  
  • follicles
  • parafollicular cells

Question 21

Endocrine gland - Thyroid gland - Thyroid histology​

Follicles

what are the walls composed of?

what does it produce?

Answer 21

• walls = epithelial cells (follicle cells)
• produce T4

Question 22

Endocrine gland - Thyroid gland - Thyroid histology

Parafollicular cells

where is it located?

what does it secrete?

Answer 22

• between follicles
• secrete calcitonin
  
  • increase Ca++ uptake into bone (bone formation) which lowers blood Ca++ bone matrix

Question 23

Endocrine glands

Parathyroid glands

where is it located and how many?

what does it secrete?

Answer 23

• 4 (usually) glands embedded in posterior thyroid
• secrete parathyroid hormone (PTH)
  
  • increase blood Ca++ by breaking down bone matrix

Question 24

Endocrine glands

Adrenal glands

where is it located?

what are the 2 parts?

Answer 24

• superior surface of each kidney
• 2 parts
  
  • adrenal cortex (outer)
  • adrenal medulla (inner)

Question 25

Endocrine glands - Adrenal glands **Adrenal cortex (outer)** what tissue? what does it secrete? how many layers? * how many hormones are secreted by each layer?

Answer 25

* epithelial tissue * secretes steroids only * 3 layers (1 hormone secreted by each): 1. Zona Glomerulosa 2. Zona Fasciculata 3. Zona reticularis

Question 26

Endocrine glands - Adrenal glands - Adrenal cortex Zona glomerulosa what does it secrete?

Answer 26

secretes mineralcorticoids (mainly aldosterone) * salt balance

Question 27

Endocrine glands - Adrenal glands - Adrenal cortex Zona fasciculata what does it secrete? * example * what kind of hormone?

Answer 27

secretes glucocorticoids (e.g. cortisol) * long term stress hormone * carbohydrate metabolism

Question 28

Endocrine glands - Adrenal glands - Adrenal cortex Zona reticularis what does it secrete?

Answer 28

secretes androgens + small amounts testosterone * some converted to estrogens in other tissues (especially fat)

Question 29

endocrine gland - adrenal gland Adrenal medulla (inner) what kind of tissue? what hormones?

Answer 29

* nervous tissue * 2 main hormones: 1. epinephrine (80%) 2. norepinephrine (20%)

Question 30

Endocrine tissues name the 4

Answer 30

Endocrine function in organs that have other functions as well: 1. Pancreatic Islets of Langerhans 2. Hypothalamus 3. Gonads 4. Others

Question 31

Endocrine tissues Pancreatic islets of langerhans

Answer 31

* 4 cell types (only covering 2 in this course) 1. a-cells 2. b-cells

Question 32

a-cells

Answer 32

produce glucagon -increases blood glucose

Question 33

b-cells

Answer 33

produces insulin -decreases blood glucose

Question 34

Endocrine tissue Hypothalamus

Answer 34

regulates anterior pituitary via: 1. GHRH (growth hormone releasing hormone) 2. GHIH (Growth hormone inhibiting hormone) 3. HnRH (Gonadotropin releasing Hormone) - FSH + LH

Question 35

Endocrine tissues Gonads

Answer 35

* Testes * leydig cells = **testosterone** * Ovaries * Cells of 1º and 2º follicles = **estrogen** * corpus luteum = **estrogen + progesterone**

Question 36

Endocrine Tissues List the others

Answer 36

* duodenum - secretin * kidney - renin * skin - vitamin D * heart - atrial natruiretic peptide (ANP) * etc.