Lecture 39: ENDOCRINE REVISION Flashcards
1
Q
Endocrine system consists of:
A
- Endocrine gland that secretes..
- Hormones (chemical messengers), which are…
- Carried in the bloodstream to…
- The target cells upon which they act
2
Q
If the target cell expresses a specific receptor…
A
- That hormone will be able to affect it
- And the target cell will be able to respond
3
Q
Water-soluble hormones:
A
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
Q
Lipid-soluble hormones:
A
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
Q
Anterior pituitary hormones:
A
- Growth Hormone
- Prolactin
- Gonadotropic hormones
- Thyroid stimulating
- Adrenocorticotropic hormone
6
Q
Posterior pituitary hormones:
A
- Antidiuretic Hormone
- Oxytocin
7
Q
Posterior pituitary gland:
A
- 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
Q
Oxytocin:
A
- 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
Q
Anterior Pituitary Gland:
A
- Neuron from hypothalamus only extends to median eminence
10
Q
Different axes:
A
- HPG
- HPT
- HPA
11
Q
Feedback regulation of the anterior pituitary gland:
A
- Hypothalamus
- Releasing Hormone
- Anterior Pituitary Gland
- Pituitary Hormone
- Target Cell
- Effector
12
Q
Effects of Growth Hormone:
A
- 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
Q
Thyroid hormones work via ______ ______.
A
- Negative Feedback
14
Q
Effects of thyroid hormone:
A
- Metabolic effect
- Growth (developmental) effects
- Via nuclear receptors that alter the transcription of genes
15
Q
C cells (calcitonin) directly sense ______ levels in the blood.
A
- Calcium
