Endocrine System Flashcards
role of endocrine system
produce hormones that release into blood
effects caused by hormone binding
- Changes in plasma membrane permeability or electrical state
- Synthesis of proteins, such as enzymes
- Activation or inactivation of enzymes
- Stimulation of mitosis (cell division)
- Promotion of secretory activity
types of endocrine glands in the body
- hypothalamus
- pituitury gland
- pineal gland
- thyriod and parathyriod
- thymus
- pancreas
- adrenal
- ovary/testicle
- placenta (pregnant)
3 ways endocrine glands can be stimulated into action
Hormonal: Most
common, glands are
stimulated by other
hormones
Humoral : changing levels of certain substances in fluids (ie ions in blood) stimulate hormone release
Neural: Nerve impulses
stimulate hormone
release ie adrenalin
Hypothalalmus
• Located in lower central part of the brain
• Secretes hormones which then stimulate or inhibit the
release of hormones from the anterior pituitary gland
• Stimulates the release of hormones from posterior
pituitary via neurons
Pituitary Gland
• Size of a pea; often called the “master endocrine gland”
• Hangs by a stalk from the hypothalamus in the brain
• Produces hormones that control many bodily functions including
reproduction, growth, water retention
• Has two functional lobes
– Anterior pituitary (hormonal stimulation)
– Posterior pituitary (nervous stimulation)
Anterior Pituitary hormones
Prolactin (PRL)
• Stimulates and maintains milk production following childbirth
Adrenocorticotropic hormone (ACTH) • Regulates endocrine activity of the adrenal cortex (releases adrenalin)
Thyroid-stimulating hormone (TSH)
• Influences thyroid gland (releases hormones that affect metabolism T3, T4)
Follicle-stimulating hormone (FSH)
• Stimulates follicle development in ovaries and sperm development in testes
Luteinizing hormone (LH) • Triggers ovulation of an egg in females and testosterone production in males
Growth hormone
• growth of skeletal muscles and long bones, causes amino acids to be built
into proteins, causes fats to be broken down for a source of energy 1
Posterior Pituitary
• the hypothalamus produces two hormones which are
transported to neurosecretory cells of the posterior pituitary
for storage
– Oxytocin
• Stimulates contractions of the uterus during labor and
breastfeeding
• Causes milk ejection in a nursing woman
– Antidiuretic hormone (ADH or vasopressin)
• Inhibits urine production by promoting water
reabsorption by the kidneys
• In large amounts, causes vasoconstriction leading to
increased blood pressure
Thyroid Gland
• metabolism
Found at the base of the throat
• Produces two hormones
– Thyroxine (T4) and Triiodothyronine (T3)
• are the major metabolic hormones
• iodine-containing hormones which control rate at
which glucose is converted to chemical energy
– Calcitonin
• Decreases blood calcium levels by causing calcium to
be deposited on the bones
Parathyroid Glands
• Attached to the thyroid are four tiny glands that
function together called the parathyroid glands.
• Hormone (PTH),
which causes the release of calcium from the bones and stimulates the kidneys and intestine to absorb more calcium when blood calcium levels drop
Adrenal Glands
• Sit on top of each kidney
• adrenal medulla:
Secretes two adrenaline (epinephrine) and noradrenaline (norepinephrine) (fight and flight)
• adrenal cortex:
produces 3 major hormones (corticosteroids)
1. aldosterone (water/balnace)
2. glucocorticoids (resist long term stressors by increasing bgl)
3. DHEA (androgen) sex hormones
pancreas
The pancreas is a mixed gland
– Produces pancreatic juice
– Produces hormones
• The pancreatic islets or islets of langerhans produce hormones
– Insulin
• released from beta cells of the islets
• allows the transport of
glucose across cell membranes
– Glucagon
• Released from the alpha cells of the islets
• causes the liver to convert stored glycogen into glucose, which is released into the bloodstream
Pineal Gland
• Found in the brain
• Secretes melatonin
– Helps establish the body’s wake and sleep cycles/circadian rhythm (high at night and low at noon)
type 1 diabetes
Progressive destruction of beta cells of the pancreas
Results in no insulin production
• Glucose cannot move into cells
• Blood glucose levels rise to abnormally high levels
• Body has to use fat and muscle to make ATP (energy)
Signs and symptoms • Polyuria - • Glycosuria- renal tubules cells cannot reabsorb glucose quickly enough • Polydipsia- • Polyphagia • Weight loss • Ketoacidosis – glucose cannot be used so body uses fat • Muscle weakness • Fatigue
Management • Insulin (SC) • Education (diet, exercise) • Monitor BGL • Regular HBA1c
type 2 diabetes
patho: insulin resistance (decreased tissue responsiveness to insulin as a result of receptor defects or lack of receptors/ decreased secretion of insulin from beta cell exhaustion)
symp:
- often asympotmatic in early stages
- diagnosis often after damage to organs or body systems.
Causes Risk Factors
• Obesity
• Age greater than 45 years
• Some ethnic groups
(particularly Indigenous Australians, African Americans, Native Americans, Asians, Pacific Islanders, and Hispanic Americans)
• Gestational diabetes a baby weighing more than 4 KGS
• High blood pressure
• High triglycerides or cholesterols
• Not getting enough exercise
• Waist measurement > 100cm Males, > 80cm women
Management • Oral hypoglycaemics • increase sensitivity of tissue to insulin • stimulate beta cells • Diet • Weight loss • Exercise • Insulin (only when other measures fail)
