Week 7: The Endocrine System

Question 1

What is homeostasis?

Answer 1

The internal environment remains relatively constant though there are changes in the external environment

Question 2

What is the endocrine system?

Answer 2

A collection of glands that secrete hormones into circulation to be carried to distant organ(s)

Question 3

Define nervous system

Answer 3

Performs short-term very specific responses to environmental stimuli

Question 4

How do the nervous system transfer messages?

Answer 4

Via chemical messengers (neurotransmitters)

Question 5

How does the endocrine system transfer messages?

Answer 5

Chemical messengers (hormones)

Question 6

What is the function of the endocrine system?

Answer 6

1) Epithelial secretory cells manufacture specific hormones
2) Hormones are then releases systemically
3) Transport of hormones to rest of body conveys specific regulatory information among cells and organs

Question 7

What are the four different ways hormones can communicate?

Answer 7

Endocrine
Autocrine
Paracrine
Juxtacrine

Question 8

Describe how hormones communicate via autocrine

Answer 8

Hormones acts directly back on the cell that has produced it

Question 9

Describe how hormones communicate via paracrine

Answer 9

Hormones acts directly upon a nearby cell

Question 10

Describe how hormones communicate via juxacrine

Answer 10

Hormonal intracellular communication between connecting cells- requires physical contact of two cells

Question 11

What is homeostasis ?

Answer 11

Maintenance of relatively constant chemical/physical conditions of the internal environment

Question 12

What is successful compensation?

Answer 12

When homeostasis is re-established

Question 13

What does it mean to fail to compensate?

Answer 13

pathophysiology/illness/death

Question 14

What is the endocrine system?

Answer 14

A collection of glands that secrete hormones into circulation to be carried to distant organs

Question 15

What are the four ways in which hormones can communicate?

Answer 15

Endocrine
Autocrine
Paracrine
Juxtacrine

Question 16

What are the three methods in which endocrine glands are stimulated to release hormones?

Answer 16

Humoral stimuli
Hormonal stimuli
Neural stimuli

Question 17

How does humoral stimuli work?

Answer 17

Changes in the composition of blood

Question 18

How does hormonal stimuli work?

Answer 18

Arrival or removal of a specific hormone

Question 19

How does neural stimuli work?

Answer 19

Nerve fibres stimulate hormone release

Question 20

What controls cellular activity?

Answer 20

Enzymes

Question 21

What do cells need to have for hormones to affect them?

Answer 21

Cells that possess specific receptors for that hormone

Question 22

What determines the magnitude of the hormone effect?

Answer 22

The number of target receptors
Concentration of the hormones
Affinity of receptor for hormone
Influence of other hormones

Question 23

What happens to a receptor during up and down regulation?

Answer 23

Up- increased number of hormone receptors

Down- decreased number of hormone receptors

Question 24

What are the two main hormone categories?

Answer 24

Steroid

Non-steroid

Question 25

What does the category of hormone determine?

Answer 25

How the hormone is transported in blood | How the hormone enters/is used by cells

Question 26

What are steroid hormones synthesized from?

Answer 26

Cholesterol

Question 27

Are steroid hormones lipid soluble?

Answer 27

Yes

Question 28

How do steroid hormones circulate the blood?

Answer 28

Bound to a carrier protein

Question 29

When steroid hormones are bound to binding proteins are the active or inactive?

Answer 29

Inactive

Question 30

Can steroids diffuse into the cell?

Answer 30

Yes

Question 31

Where are the specific steroid receptors are located?

Answer 31

Cytoplasm or nucleus

Question 32

What does the steroid hormone do once it's in the nucleus and what does that lead to?

Answer 32

Activate gene expression therefore protein synthesis is induced

Question 33

Are non-steroid hormones water-soluble?

Answer 33

Yes

Question 34

What is the molecular weight of non-steroid hormones and what effect does this have?

Answer 34

High molecular weight therefore cannot diffuse across the cell membrane

Question 35

Where do non-steroid hormones interact/bind with receptors?

Answer 35

On the cell's plasma membrane

Question 36

What is signal transduction?

Answer 36

The process by which extracellular signals are communicated into a cell to affect function

Question 37

What is the most common type of feedback loop?

Answer 37

Negative feedback

Question 38

What happens during a negative feedback loop?

Answer 38

Stimulus activates endocrine gland Endocrine gland secretes hormone into blood stream Target cell respond to hormone alter original stimulus This signal then reaches original endocrine gland to switch-off further hormone production

Question 39

Describe what the negative feedback loop does in simple terms

Answer 39

The output inhibits the input

Question 40

What hormone is lipid soluble?

Answer 40

Steroid

Question 41

What does receptor down regulation mean?

Answer 41

The number of receptors on a cell decreases

Question 42

What are the two lobes of the pituitary gland?

Answer 42

Anterior lobe | Posterior lobe

Question 43

What does the posterior lobe of the pituitary gland do?

Answer 43

Stores hormones made by hypothalamic neurons and releases into circulation (does not synthesise hormones)

Question 44

What does the anterior lobe of the pituitary gland do?

Answer 44

Receives hypothalamic hormones which stimulates further hormone release by pituitary gland

Question 45

What does the pineal gland produce?

Answer 45

Melatonin

Question 46

Where is the thyroid gland located?

Answer 46

In the neck inferior to the larynx

Question 47

What does the thyroid gland secrete?

Answer 47

T3 and T4

Question 48

What is the thyroid gland involved in?

Answer 48

Tissue development and growth and macronutrient metabolism

Question 49

Where is the parathyroid gland located?

Answer 49

Posterior of the thyroid gland

Question 50

What does the parathyroid gland produce?

Answer 50

Parathyroid hormone (PTH)

Question 51

What ion is the parathyroid hormone the most important regulator of?

Answer 51

Ca2+

Question 52

What does parathyroid hormone stimulate?

Answer 52

Ca2+ re-absorption at kidney, and calcium resorption at bone

Question 53

What are the two types of functions that the pancreas has?

Answer 53

Exocrine | Endocrine

Question 54

What is the endocrine function of the pancreas?

Answer 54

Secretes substance (i.e. insulin) to regulate blood glucose levels

Question 55

What is the exocrine function of the pancreas?

Answer 55

Secretes enzymes to digest exogenously obtained substances (i.e. carbohydrates)

Question 56

In the pancreas, what do alpha cells do and why?

Answer 56

Produce glucagon therefore increase blood glucose

Question 57

In the pancreas, what do beta cell do and why?

Answer 57

Insulin to decrease blood glucose

Question 58

In the pancreas, what do delta cells do and why?

Answer 58

Produce gastrin/somatostatin to regulate alpha and beta cells

Question 59

In the pancreas, what do F cell do and why?

Answer 59

Pancreatic polypeptide to regulate metabolism

Question 60

Where are the adrenal glands located?

Answer 60

Superior to each kidney

Question 61

What are the two portions of the adrenal glands called?

Answer 61

Outer adrenal cortex | Inner adrenal medulla

Question 62

What are the way in which the endocrine system can fail?

Answer 62

Abnormal hormone receptor function/levels Altered intracellular response to the hormone receptor complex Hyper or hyposecretion of hormones by glands

Question 63

In the adrenal medulla what happens when the sympathetic nerve fibres stimulate it?

Answer 63

Stimulates the release of neurotransmitters epinephrine (adrenaline) and norepinephrine

Question 64

Where are the epinephrine and norepinephrine alpha receptors found?

Answer 64

In sympathetic organs/tissues

Question 65

Where are the epinephrine and norepinephrine beta receptors found?

Answer 65

Located on membranes of many organs, including muscles, lungs, heart and liver

Question 66

What are catecholamines?

Answer 66

Hormones secreted by the adrenal glands

Question 67

What happens to glucagon when insulin levels increase?

Answer 67

Production decreases