Endocrinology Flashcards
Similarities of endocrine and nervous systems
1)Receptors
2)Chemical messengers
3)Elicit a response
Differences between endocrine and nervous systems
1)Transmission speed
2)Duration of response
3)How chemicals are transmitted
Endocrinology
Study of chemical messengers and the glands/tissues they are secreted from
Signalling that occurs in the endocrine system
1)Chemical messenger release
2)Transport of the messenger
3)Binding of messenger/initiating response
2 ways to classify hormones
Chemical structure & where they bind to receptors
Where can hormones bind?
Intracellularly or on the plasma membrane
Types of hormones
Peptides/proteins, biogenic amines, steroids and eicosanoids
Difference between peptide and protein hormones
Number of aa present (peptides are shorter; <50)
Examples of peptide hormones
TSH and TRH
Where are peptide hormones synthesized?
rER
What is an amine?
Chemicals that possess an amine group; usually synthezied from aa
Examples of biogenic amines
Catecholamines/thyroid hormones
Where can steroid hormones be produced?
Gonads or adrenal cortex
3 major classes of steroid hormones
1)Glucocorticoids
2)Mineralocorticoids
3)Reproductive hormones
What does hormone response intensity depend on?
Hormone/receptor concentration and receptor affinity
What are different ways for a hormonal response to terminate?
Inactivation of the specific receptor, ligand-receptor complex endocytosed or degraded by extracellular enzymes
Negative feedback
Maintains constant levels
Positive feedback
Purposeful amplification of a certain response; explosive effect
Additive effects
Resulting effect is equal to the sum of effects of each hormone
Synergistic effects
Resulting effect is greater than the sum of each hormone
Hypothalamus (location/function)
Diencephalon (forebrain); controls function of the pituitary and regulation of body (temperature/bp)
Pituitary Gland (hypophysis)
Most important endocrine gland; double lobed (anterior and posterior)
What is the name of the stalk that connects the hypothalamus and pituitary?
Infundibulum
What system is involved in the activation of the anterior pituitary?
Portal system
What system is involved in the activation of the posterior pituitary?
Direct secretion of a neurohormone
Neurohaemal organs
Structures where neurons secrete directly to the blood
Eg: Median eminence, posterior pituitary
Trophic hormones
Hormones that cause the release of other hormones (3rd order)
What is stress?
Disturbance to the organism’s equilibrium dynamic (result from intrinsic or extrinsic stressors)
2 types of stress response
Acute or chronic
Acute stress
Used in a stressful moment to overcome a threat (increases survival and fitness)
Chronic stress
Long-term and can be maladaptive, where the animal is in constant panic
3 phases of stress response
Primary (elevated stress hormones), secondary (responses initiated by stress hormones), tertiary (changes in whole animal performance)
Where are catecholamines released from?
Chromaffin cells in the adrenal gland
Where are glucocorticoid hormones released from?
Interrenal cells in the adrenal gland
Response from catecholamines
Increased O2 delivery and mobilizes energy reserves
Where are catecholamine receptors?
On membrane
Where are glucocorticoid receptors?
In the cytoplasm
