Lecture 39: ENDOCRINE REVISION Flashcards Preview

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Flashcards in Lecture 39: ENDOCRINE REVISION Deck (24):
1

Endocrine system consists of:

- Endocrine gland that secretes..
- Hormones (chemical messengers), which are...
- Carried in the bloodstream to...
- The target cells upon which they act

2

If the target cell expresses a specific receptor...

- That hormone will be able to affect it
- And the target cell will be able to respond

3

Water-soluble hormones:

Water-soluble hormones
- Peptides
- Catecholamines
- Stored until required
- Dissolved in the blood
- Receptors on the cell surface
- Mechanism of action via 2nd messengers
- Speed = milliseconds - minutes

4

Lipid-soluble hormones:

Lipid-soluble hormones
- Steroids
- Thyroid hormones
- Made from cholesterol as required (not stored)
- Thyroid hormones made in thyroid cells, stored until required
- Bound to carrier protein
- Intracellular receptors
- Alter gene transcription
- Speed = hours - days

5

Anterior pituitary hormones:

- Growth Hormone
- Prolactin
- Gonadotropic hormones
- Thyroid stimulating
- Adrenocorticotropic hormone

6

Posterior pituitary hormones:

- Antidiuretic Hormone
- Oxytocin

7

Posterior pituitary gland:

- Neuron starting from hypothalamus extends to posterior
- Hormone made and synthesised in hypothalamus and stored in axon
- Secretes hormone into posterior pituitary gland
- Main hormone secreted = oxytocin

8

Oxytocin:

- Fetus moves into birth canal, stretch increase
- Variable = stretch
- Detected by stretch receptors
- Feeds information via nerve fibres back to hypothalamus + pituitary
- Hormone (OT) stimulates muscle
- Stronger, more frequent labour contractions
- Uterine muscle = effector
- POSITIVE FEEDBACK = response increases stimulus

9

Anterior Pituitary Gland:

- Neuron from hypothalamus only extends to median eminence

10

Different axes:

- HPG
- HPT
- HPA

11

Feedback regulation of the anterior pituitary gland:

- Hypothalamus
- Releasing Hormone
- Anterior Pituitary Gland
- Pituitary Hormone
- Target Cell
- Effector

12

Effects of Growth Hormone:

- Long Term
Growth of bones, muscles, and other tissues indirectly via insulin-like growth factor (IGF-1)
Stimulates protein synthesis
- Short Term
Increases blood glucose
Increases triglyceride breakdown

13

Thyroid hormones work via ______ ______.

- Negative Feedback

14

Effects of thyroid hormone:

- Metabolic effect
- Growth (developmental) effects
- Via nuclear receptors that alter the transcription of genes

15

C cells (calcitonin) directly sense ______ levels in the blood.

- Calcium

16

Calcitonin :

- Lowers high Ca2+ levels so that they're back to normal.

17

Parathyroid hormone ______ ____ Ca2+ back to normal.

- Raises low
- Kidney hydroxyapatite affected
- Less urinary calcium excretion

18

Adrenal Glands located at the top of the kidney. Broken into two main parts:

- Cortex: inner, middle, outer
- Medulla : epinephrine, norepinephrine (catecholamines) --> have the same function on target cells

19

Cortisol Secretion:

- Abnormal stress / daily variation
- Hypothalamus : corticotropin releasing hormone
- AP : secretes adrenocorticotropic hormone
- Adrenal Cortex: Cortisol
- Metabolic effects: increased protein breakdown, fat breakdown, glucose synthesis
- Negative feedback (except during stress response)
- Other effects: helps one cope with stress, long-term: suppresses immune system

20

Constant Glucose Levels:

- Alpha cells and Beta cells sense and integrate glucose levels

21

Insulin regulates _____ storage.

- Fuel

22

Glucagon regulates fuel _____.

- Release

23

Type 2 Diabetes = _____ of beta cells. Two completely pathways between

- Hypertrophy

24

Type 1 = ZERO insulin. Type 2 = Insulin level is also lowered

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