endocrine system Flashcards
What is homeostasis?
A state of overall internal chemical and physical stability that is required for the survival of cells and the body
What do homeostatic mechanisms do?
Maintain a constant internal environment despite a variable external environment
What does deviation from homeostasis indicate?
Disease
What is a set point?
The physiological value around which the normal range fluctuates
What is a negative feedback loop?
A feedback loop where the the effect opposes the original stimulus
What are the elements of a feedback loop
Stimulus, receptor, integrator, effector, response
What is positive feedback?
Where the response increases the original stimulus
Pathway of steroids hormones
lipid soluble - diffuse directly through the cell membrane
enter the cytoplasm
enter the nucleus
form a hormone receptor complex (transcription factor)
binds to promoter regions of genes
stimulates or inhibits the transcription of those genes
What are the two types of hormones?
Lipid hormones
Non lipid hormones, peptides
Pathway of peptide hormones
binds to a receptor on the cell membrane
- activates a Secondary messenger
Paracrine
Hormone stimulates a nearby cell, travels through extra cellular material
Autocrine
The hormone secretion acts on the cell itself or cell type
Which hormones does the anterior pituitary secrete?
ACTH, TSG, FSH, LH, GH, prolactin
Which hormones does the posterior pituitary produce?
ADH, oxytocin
What does the adrenal cortex secrete
Cortisol, aldosterone, sex hormones