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Mr. Wright 2011 Chapter 11:. The Endocrine System. Section 11.1. Introduction. The Endocrine System. The body has two systems designed for communication: The Nervous System The Endocrine System Allows the body to change to different situations. The Endocrine System. Made up of glands.

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the endocrine system
The Endocrine System
  • The body has two systems designed for communication:
    • The Nervous System
    • The Endocrine System
  • Allows the body to change to different situations.
the endocrine system1
The Endocrine System
  • Made up of glands.
  • Glands secrete hormones.
  • Hormones enter the bloodstream and are carried to specific target cells.
local hormones
Local Hormones
  • Some hormones never enter the bloodstream… they stay in the same area and are called local hormones.
    • Paracrine – affect neighboring cells
    • Autocrine – affect the secreting cells themselves.
exocrine glands
Exocrine Glands
  • Exocrine glands secrete things outside the body.
    • Example: Sweat
comparing nervous endocrine
Comparing Nervous & Endocrine
  • Involved in communication.
  • Releases neurotransmitters into synapses.
  • Very precise.
  • Very brief.
  • Involved in communication.
  • Releases hormones into bloodstream
  • Very precise.
  • Can be brief or very long.

Nervous System

Endocrine System

things the endocrine system controls
Things the Endocrine System Controls…
  • The endocrine system regulates many metabolic processes.
    • Rates of chemical reactions.
    • Transport across membranes.
    • Regulate water and electrolyte balances.
    • Reproduction
    • Development
    • Growth
hormones
Hormones
  • There are 3 main types of hormones:
    • Steroids
    • Nonsteroids
    • Prostalandins
steroid hormones
Steroid Hormones
  • Steroid hormones are made or rings of carbon and hydrogen atoms.
  • They are insoluble in water, but are soluble in lipids (fats) like cell membranes.
    • Thus, they can enter and exit cells easily.
nonsteroid hormones
Nonsteroid Hormones
  • Nonsteroid hormones cannot enter cells.
  • Instead, they combine with receptors in the cell membrane.
prostaglandins
Prostaglandins
  • Prostaglandins are special lipids synthesized from fatty acids in the cell membrane.
  • Produced in the liver, kidneys, heart, lungs, brain, and several endocrine glands.
prostaglandins1
Prostaglandins
  • Produce many diverse effects.
    • Relax/Contract smooth (involuntary) muscles.
    • Stop production of stomach acid.
    • Influence movements of salt and water in the kidney.
    • Regulates blood pressure.
    • Stimulates other hormones.
hormonal secretions
Hormonal Secretions
  • As hormone levels increase in the blood, hormone secretion decreases.
    • The more there is, the less we need.
    • The opposite of this statement is true as well.
hormonal secretions1
Hormonal Secretions
  • Hormonal secretion is controlled by negative feedback.
    • Negative feedback – the mechanism is controlled by an imbalance that corrects it.
examples of negative feedback
Examples of Negative Feedback
  • The hypothalamus stimulates the pituitary gland to secrete hormones.
  • The pituitary gland secrets hormones which stimulate the ovaries to secrete hormones needed for puberty.
  • If the ovary hormone levels in the blood are too high, the hypothalamus stops stimulation.
examples of negative feedback1
Examples of Negative Feedback
  • When blood sugar levels are high, the pancreas secretes insulin.
  • Blood sugar levels decrease.
  • Once blood sugar levels are low enough, pancreas stops secreting insulin.
conclusion
Conclusion
  • As a result of negative feedback, hormone levels in the blood remain relatively stable, with only slight changes.
structure
Structure
  • The pituitary gland is found hanging beneath the brain.
  • Very small.
  • Attached to the brain by a small stalk called the infundibulum.
  • 2 halves:
    • Anterior
    • Posterior
function
Function
  • Controlled mostly by the brain.
  • Releasing hormones – hormones the brain (hypothalamus) secretes to signal the pituitary to release its hormones.
  • Each releasing hormone acts on a specific part of the pituitary.
hormones anterior
Hormones - Anterior
  • Human Growth Hormone (HGH)
    • Stimulates cells to increase in size and divide more frequently.
    • HGH is released when there are low protein or sugar levels in the blood.
    • Disorders:
hormones anterior1
Hormones - Anterior
  • Prolactin (PRL)
    • Pro- = with, for
    • -lactin = milk
    • Stimulates milk production in females.
    • PRL is found in males.
      • Excess PRL in males decreases the amount of male sex hormones.
hormones anterior2
Hormones - Anterior
  • Thyroid-Stimulating Hormone (TSH)
    • Controls the secretion of hormones by the thyroid.
  • Adrenocorticotropic Hormone (ACTH)
    • Controls the secretion of hormones by the adrenal gland.
hormones anterior3
Hormones - Anterior
  • Follicle-Stimulating Hormone (FSH)
    • Stimulates the gonads.
    • Gonads – reproductive organs
      • Testes in males
      • Ovaries in females
    • Remember what follicles are?
hormones posterior
Hormones - Posterior
  • Antidiuretic Hormone (ADH)
    • Decreases urine formation.
    • Does this by lowering the amount of water secreted by the kidneys.
    • Stimulated by fluid levels in the body.
hormones posterior1
Hormones - Posterior
  • Oxytocin (OT)
    • Stimulates uterine contractions during childbirth.
    • Contracts smooth muscles in the uterus.
    • Stimulated by stretching of uterine and vaginal tissues.
structure1
Structure
  • Consists of two lobes connected by the isthmus.
  • Just below the larynx and in front of the trachea.
thyroid hormones
Thyroid Hormones
  • Thyroxine (T4)
    • Regulates the metabolism of sugars, lipids, and proteins.
    • Determines how many calories you need to consume to live.
thyroid hormones1
Thyroid Hormones
  • Triiodothyronine (T3)
    • Same function as Thyroxine, though this is 5 times more potent.
    • Both are stimulated by iodine levels in the body.
    • This iodine comes from food.
thyroid hormones2
Thyroid Hormones
  • Calcitonin
    • Increases calcium and phosphate concentrations in the blood.
    • Does this by regulating osteoclast/osteoblast activity and the kidneys.
thyroid problems
Thyroid Problems
  • Cretinism
    • Caused by not having enough thyroid activity (hypothyroidism).
    • Symptoms:
      • Stunted Growth
      • Abnormal Bones
      • Mental Retardation
      • Sluggishness
thyroid problems1
Thyroid Problems
  • Goiters
    • Too much thyroid activity (hyperthyroidism) leads to a swelling of the tissues behind it.
    • This causes a large bulge in the neck called a goiter.
structure2
Structure
  • You have four.
  • They are very small.
  • Found on the posterior thyroid.
  • Covered in CT.
parathyroid hormone
Parathyroid Hormone
  • Parathyroid Hormone (PTH)
    • Increases blood calcium levels and decreases blood phosphate levels.
    • Similar to calcitonin.
structure3
Structure
  • Located superior to the kidneys… sits on top of them like a cap.
  • Made up primarily of epithelial cells and blood vessels.
  • 2 parts:
    • Adrenal medulla – center
    • Adrenal cortex - outsides
hormones adrenal medulla
Hormones – Adrenal Medulla
  • Epinephrine and Norepinephrine
    • Similar in structure and function.
    • Epinephrine is actually made from norepinephrine.
    • Several effects:
      • Increases heart rate.
      • Elevates blood pressure.
      • Increases blood sugar.
      • Addictive
    • ADRENALINE!!!
disorders adrenaline
Disorders - Adrenaline
  • People who have too much adrenaline produced will suffer from high blood pressure, high blood sugar levels, increased heart rate, etc… hypertension.
disorders adrenaline1
Disorders - Adrenaline
  • Those who do not have enough adrenaline produced may be lackadaisacal and/or unexcitable – hypotension.
hormones adrenal cortex
Hormones – Adrenal Cortex
  • Aldosterone
    • Helps regulate the concentration of minerals. (Na and K)
    • Does this by increasing water retention.
hormones adrenal cortex1
Hormones – Adrenal Cortex
  • Cortisol
    • Increases glucose levels in the blood.
    • Very similar to T3 and T4.
hormones adrenal cortex2
Hormones – Adrenal Cortex
  • The adrenal cortex also produces some sex hormones.
  • This is not the primary source of these hormones, however, so we will talk about them more once we get to the gonads next week.
structure4
Structure
  • Long, flattened organ behind the stomach.
  • Connected to the small intestine by a small duct.
structure5
Structure
  • Has two functions:
    • Digestive (Will discuss later)
    • Endocrine
  • The endocrine cells are arranged into special groups called islets of Langerhans.
    • Alpha cells
    • Beta cells
hormones pancreas
Hormones - Pancreas
  • Glucagon
    • Raises blood sugar concentration.
      • More effective than epinephrin/norepinephrin
    • Released by alpha cells.
hormones pancreas1
Hormones - Pancreas
  • Insulin
    • Lowers blood sugar concentration.
    • Direct opposite to glucagon.
    • Released by beta cells.
    • Often released after eating.
disorder diabetes
Disorder - Diabetes
  • Caused by an insulin deficiency.
  • Blood sugar levels rise.
  • The kidneys will excrete excess sugars into urine, which also causes more water to be added.
    • Leads to dehydration and extreme thirst.
disorder diabetes1
Disorder - Diabetes
  • Insulin also helps glucose move into cells, which means this isn’t happening anymore.
  • Cells will break down proteins instead, causing tissues to disappear and leading to weight loss.
type 1 diabetes
Type 1 Diabetes
  • Autoimmune disease – the body’s immune system destroys its own beta cells.
  • Also called juvenile diabetes.
  • Treated via insulin injections.
type 2 diabetes
Type 2 Diabetes
  • Develops in people over age 40.
  • Milder symptoms.
  • Generally seen in overweight people.
  • Beta cells work, but body cells lose sensitivity to insulin so injections don’t work.
  • Treated via diet changes, exercise, etc.
the pineal gland
The Pineal Gland
  • Small structure located deep between the cerebral hemispheres.
hormones pineal gland
Hormones – Pineal Gland
  • Melatonin
    • Released in response of light amounts outside of the body.
      • More is released in the dark.
    • Responsible for your “biological clock”
      • Circadian rhythm
      • Determines daily sleep cycle, but also puberty and menstrual cycle.
thymus gland
Thymus Gland
  • Found posterior to the sternum, in between the lungs.
  • Large in children but shrinks with age.
hormones thymus
Hormones - Thymus
  • Thymosins
    • Produce white blood cells.
    • Also determines the type of each white blood cell.
    • Will discuss more when we get to immune system.
reproductive glands
Reproductive Glands
  • Include the ovaries, placenta, and testes.
  • Will be discussed in much more detail when we get to that chapter.
hormones gonads
Hormones - Gonads
  • Females
    • Estrogen
    • Progesterone
  • Males
    • Testosterone
  • Will discuss in more detail later.
stress
Stress
  • When the body senses danger, it triggers physiological responses designed to take care of it.
    • Includes an increase in certain hormones.
  • This condition is called stress.
  • Anything that causes it is called a stressor.
types of stress
Types of Stress
  • Physical – temperature, oxygen levels, infection, injury, etc.
  • Psychological – thoughts, feelings, sense of loss, unpleasant social interactions
  • Doesn’t have to be a negative thing, either. Can be friendly contact, feelings of joy, sexual arousal, etc.
responses to stress
Responses to Stress
  • Controlled by the hypothalamus of the brain.
    • “Fight or Flight”
  • Things your body does:
    • Raise blood sugar levels
    • Increase heart rate, blood pressure, breathing rate
    • Excess blood to muscles
    • Increases epinephrine levels
stress drawbacks
Stress Drawbacks
  • These reactions can cause:
    • High blood pressure
    • Ulcer formation
    • Lower WBC count/increased risk of infection.