Endocrine Flashcards
Where are exocrine substances secreted?
Into the ducts and onto the lumen?
Where are endocrine substances secreted?
Into the bloodstream
Do exocrine substances act at distance or locally?
Locally
Do endocrine substances act locally or at distance?
At distance
What system works closely with the endocrine system?
Nervous system
The nervous system releases x at y
Neurotransmitters at synapses
The endocrine system releases x into y
Hormones into the bloodstream
How do hormones work?
They bind to specific receptors on target cells
What are the two main groups of hormones?
Lipid soluble (steroids) Water soluble (proteins)
What do water soluble proteins require?
A second messenger
Where are the receptors for lipid soluble hormones?
Inside cells
What is the common 2nd messenger molecule in cells
cAMP
What does cAMP do?
It activates corresponding enzymes that catalyse reactions
What occurs after a lipid soluble hormones complexes in the cell?
It results in a change in gene expression leading to the production of mRNA which in turn allows the synthesis of specific proteins which later cell activity
What does the pituitary gland do?
Produces lots of hormones that control glands
What does the hypothalamus do?
Controls the pituitary gland
What are the two parts of the pituitary gland?
Posterior (30%)
Anterior (70%)
What is the posterior pituitary made up of?
Nervous tissue
What two hormones are stored and released from the post. Pit?
Oxytocin
ADH
What cells secrete oxytocin and ADH?
Neurosecretory cells
What is the ant. Pit made up of?
Glandular tissue
What 6 hormones are released from the Ant Pit?
- GH
- FSH
- LH
- Prolactin
- ACTH
- Thyrotropic
Why is oxytocin important?
It is involved in milk ejection and uterine contractions
What is ADH involved in?
H20 reabsorption at the kidney (to decrease urine output)
In what 3 ways can hormone secretion be stimulated?
- Signals from the NS
- Chemical changes in the blood
- Other hormones
What two thyroid hormones influence metabolic rate?
Thyroxine (T4)
Triiodothyronine (T3)
What hormone stimulates TSH release?
TRH
What two hormones regulate blood glucose?
Insulin and Glucagon
Where is insulin produced?
Beta cells - Islets of langerhaus in the pancreas
Where is glucagon produced?
Alpha cells - Islets of langerhaus
What does insulin do?
Decreases blood glucose by promoting cells to take up glucose
What does glucagon do?
Glucagon promotes the liver to release glycogen stores in the event of low blood sugar
What hormone is in a positive feedback loop?
Oxytocin
What are the 2 parts of the adrenal gland?
Cortex and Medulla
What main hormones are produced in the adrenal glands?
- Mineralocorticoids
2. Glucocorticoids
What two substances are produced by the central adrenal medulla?
- Adrenaline
- Noradrenaline
What are three ways in which endocrine disorders can occur?
- Excess hormone (tumours of the hypothalamus or pituitary)
- A lack of hormone
- Reduced sensitivity of target cells (type 2 diabetes)
What do thyroid hormones do?
They set the basal metabolic rate
What are some of the cardinal signs of HYPOthyroidism?
Decreased BMR Weight gain Slow heart rate Cold and tired TREAT WITH THYROXINE
What are some of the cardinal signs of HYPERthyroidism ?
Increased BMR Weight loss Warm Fast HR Shaky Anxious
What element is essential in making thyroid hormones?
Iodine
What are two reasons for endemic IDD?
Lack of seafood
Poor iodine levels in soil
