second great controlling system of the body body system that contains internal organs that secrete...
TRANSCRIPT
What is the endocrine system?
Second great controlling system of the body
Body system that contains internal organs that secrete hormones.
So, where do hormones work?
So glad you asked that question! Target cells or target organs
Location where a given hormone affects
What do hormones do?
Hormones cause certain changes. What are these changes?
Changes in plasma membrane permeability or electrical state
Synthesis of proteins or certain regulatory molecules (enzymes) in the cell.
Activation or inactivation of enzymes Stimulation of mitosis
In English please…
Hormones control all activities in the body
They alter or change functions of cell to get a response
3 types of hormones
Steroidal Hormones Insoluble in water, carried in the blood and
released near the vicinity of the target cell Nonsteriodal hormones
Unable to enter target cells and instead bind to receptors situation on the target cell’s plasma membrane
Prostaglandins act locally, affecting only the organ where
they are produced
What controls hormones?
Negative feedback The chief means of regulating blood levels of
nearly all hormones Triggered by some internal or external
stimulus Rising hormone levels inhibit further hormone
release In other words, a stimuli triggers
hormone production… then that hormone may either stimulate or inhibit other hormones
Pituitary
Structure Size of grape Located at the
base of the brain Attached to the
hypothalamus 2 parts
Anterior pituitary Posterior pituitary
Function Often called the
“master gland” because of its great influence on the body organs
Hormones of the Anterior Pituitary Gland
Prolactin (PRL) Stimulates milk production in women after childbirth Can affect sex hormone levels in men and women
Growth hormone (GH) Stimulates growth in childhood Important for maintaining healthy body composition In adults, important for muscle mass, bone mass,
and fat distribution Adrenocorticotrophin (ACTH)
Stimulates production of cortisol (“stress hormone”) by adrenal gland. Helps maintain blood pressue and blood glucose levels
More…
Thyroid stimulating hormone (TSH) Stimulates thyroid to produce thyroid hormones Thyroid hormones – regulate metabolism,
energy, growth, and development Lutenizing homone (LH)
Regulates testosterone in men and estrogen in women
Follicle Stimulating hormone (FSH) Promotes sperm production in men Stimulates ovaries to release eggs (ovulate) in
women
Posterior Pituitary Hormones
Oxytocin Causes milk letdown in nursing mothers and
contractions during childbirth Antidiuretic hormone (ADH)
Regulates water balance If not secreted properly can lead to kidney
problems and too much sodium
Thyroid Gland
Structure Small gland in
back of neck In front of trachea
and below Adam’s apple
Function Controls
metabolism
Thyroid Gland Hormones
Thyroxin Increase rate at which cells release energy
from carbs Calcitonin
Regulates the blood concentration of calcium
Thyroid Disorders
Hypothyroidism Stunted growth Mental retardation Sluggish Weight gain in adults
Hyperthyroidism (Grave’s disease) Restlessness Weight loss Anxiety Can cause Goiter (enlarged thyroid)
Parathyroid gland
Structure Behind thyroid Four tiny glands
Function Help maintain
calcium and phosphorus levels
Parathyroid Hormones
Parathyroid hormone (PTH) Takes calcium from bones to make it available
in the blood
Parathyroid disorders
Hyperparathyroidism Can be caused by a tumor Increases PTH secretion Bones soften Too much calcium can cause kidney stones
Hypoparathyroidsm Too little PTH Too little calcium affects nervous system
Adrenal Glands
Structure 2 organs… 1
located above each kidney
Function Outer portion
called adrenal cortex and are essential for life
Inner portion is the adrenal medulla and are not essential for life
Hormones of the Adrenal Medulla
Epinephrine & Norepinephrine Increased heart rate, breathing rate, elevated
blood pressure (fight or flight response to stress)
Hormones of the Adrenal Cortex
Aldosterone Helps kidneys conserve sodium and excrete
potassium, maintaining blood pressure Cortisol
Keeps blood glucose stable Adrenal Sex Hormones
Androgens (male) and estrogens (women)
Adrenal Disorders
Cushing’s Syndrome Hypersecretion of cortisol Blood glucose remains high, retains too much
sodium, puffy skin, masculinzing effects in women
Addison’s Disease Hyposecretion Decreased blood sodium, dehydration, low
blood pressure, increased skin pigmentation
Pancreas
Structure Large gland behind
stomach
Function Helps body
maintain healthy blood sugar levels
Contains islands of cells called islets of Langerhans which secrete glucagon and insulin
Hormones of Pancreas
Glucagon Stimulates liver to break down glycogen,
raises blood sugar Insulin
Decreases blood sugar concentrations, affects the uptake of glucose cells
Disorders Related to the Pancreas
Diabetes Mellitus Results from an insulin deficiency, blood sugar
rises and excess is excreted in the urine Type I
Insulin dependent; often inherited immune disorder that destroys pancreatic cells
Type II Can be controlled with diet and exercise
Hypoglycemia Low blood sugar; can be caused by too much
insulin
Pineal Gland
Located between the cerebral hemispheres
Secretes melatonin Important for maintaining Circadian
rhythums (light and dark activity)
Thymus Gland
Large in young children Gradually shrinks with age Secretes thymosins – important to
immune function