Physiology Flashcards
Define the Endocrine system
System which controls organ function via the release of hormones (ductless endocrine glands), which then travel via the blood to a distal site of action
Exert their effects at very low concentrations
Must have action terminated (negative feedback)
Secreted in short bursts (24hr monitoring)
How does the Endocrine system differ from the Nervous system?
Nervous:
Local site of actions
Crossing a synapse
Released from a Neurone (neurotransmitter chemicals)
Endocrine:
Distant site of actions
Transported through the blood
Released from a cell, tissue or gland
What is a Neurohormone?
Nerve cell relates a chemical into the blood which is then transferred to a distal site of action (hypothalamus hormones)
What is a difference between Endocrine, Autocrine, Paracrine & Exocrine Glands
Endocrine are ductless and secrete into the blood (Insulin)
Exocrine have ducts and secrete into the external environment (Bile)
Autocrine cells secretions bind to the same cell (Cytokines)
Paracrine cell secretions bind to a neighbouring cell through diffusion in the ECF (Histamine)
Pineal Gland:
Hormone
Primary Target
Main Effect
- Melatonin
- Brain & Other Tissues
- Circadian rhythms / Immune function / Antioxidant
Hypothalamus:
Hormone
Primary Target
Main Effect
- Trophic hormones
- Anterior pituitary
- Release or inhibition of pituitary hormones
Posterior Pituitary:
Hormone
Primary Target
Main Effect
- Oxytocin / Vasopressin
- Kidneys, Breasts & Uterus
- Milk ejections, Labour & Water retention
Thyroid Gland:
Hormone
Primary Target
Main Effect
- Triiodothyronine, Thyroxine & Calcitonin
- Bone & Other Tissues
- Metabolism, Growth, Development & Plasma calcium levels
Parathyroid Gland:
Hormone
Primary Target
Main Effect
- Parathyroid hormone
- Bone & Kidney
- Regulate plasma Ca & Phsophate levels
Thymus Gland:
Hormone
Primary Target
Main Effect
- Thymosin & Thymopoietin
- Lymphocytes
- Lymphocyte development
Heart Cells:
Hormone
Primary Target
Main Effect
- Atrial naturalistic peptide
- Kidneys
- Increases Na excretions
Liver Cells:
Hormone
Primary Target
Main Effect
- Angiotensinogen / Insulin-like growth factor
- Adrenal cortex, blood vessels & other tissues
- Increase Blood Pressure / Growth
Stomach & Intestines:
Hormone
Primary Target
Main Effect
- Gastrin, Cholecystokinin & Secretin
- GI tract & Pancreas
- Assist digestion and absorption
Pancreas
Hormone
Primary Target
Main Effect
- Insulin, Glucagon, Somatostatin & Pancreatic polypeptide
- Many tissues
- Metabolism of glucose
Anterior Pituitary:
Hormone
Primary Target
Main Effect
- Prolactin, Somatotopin, Corticotropin, Thyrotropin, Folicle-stimulating & Luteinzing
- Breast, Liver, Adrenal cortex, Thyroid & Gonads
- Milk Production, Growth, Cortisol release, Thyroid hormone synthesis, Effective or sperm production
Adrenal Cortex:
Hormone
Primary Target
Main Effect
- Aldosterone, Cortisol & Androgens
- Kidney & Other tissues
- Na & K homeostasis, Stress response & sex drive in females