Anatomy and Physiology

1
Chapter 7
2
Anatomy and Physiology

• Chapter 7
• The Endocrine Glands and Hormones

3
Applied Learning Outcomes
Use the terminology associated with the endocrine
system Learn about hormones, glands, and their
functions Understand the aging and pathology of
the endocrine system
Chapter 7 The Endocrine Glands and Hormones
4
Overview

• The endocrine system is a complex collection of
  hormones that coordinate many of the bodys
  functions.
• It is composed of glands that produce endocrine
  secretions.
• Endocrine secretions are cellular signals that go
  directly into the blood.

Chapter 7 The Endocrine Glands and Hormones
5
Jobs of the Endocrine System

• Controls blood sugar
• Maintains salt and water balance
• Controls development and growth
• Controls blood pressure and heart rate
• Nervous system works with the endocrine system in
  response to danger and stress
• Regulates metabolism
• Determines gender and fertility
• Controls human reproduction

6
Glands

• A group of cells that manufacture secretions.
• Two types of glandular secretions
• Exocrine- deposited into the body cavity or
  surface
• of skin through a tunnel of cells or ducts
• Endocrine secretions typically sent into blood
• Receive signals from environment (such as
  atmospheric gases, gravity, nutrients, sunlight,
  temperature)
• Receives cellular signals or hormones that
  originate inside the body
• Almost any organ in the body can produce
  endocrine secretions.

7
Endocrine System

• Composed of 10 endocrine glands.
• Called ductless glands
• They do not travel through tubes. Enter blood
  stream.
• Cells with certain receptors respond to endocrine
  secretions.
• Target cells are cells that have these receptors.

8
The Endocrine Glands Pituitary and Pineal
Chapter 7 The Endocrine Glands and Hormones
9
The Pituitary Gland and its Secretions

• Pituitary gland (Anterior)
• Growth Hormone (GH) Affects Bone
• Adrenocorticotropic hormone (ACTH) Affects
  Adrenal cortex
• Thyroid stimulating hormone (TSH) Affects Thyroid
  gland
• Follicle Stimulating Hormone (FSH) affects
  ovaries and testes
• Lutenizing hormone (LH) affects ovaries and
  testes
• Melanocyte stimulating hormone (MSH) affects Skin
• Prolactin affects Mammary glands(PRL)
• Pituitary gland (Posterior)
• Oxytocin affects Mammary glands(OT)
• Oxytocin affects Uterus
• Antidiuretic hormone (ADH) affects Kidney tubules

10
Hormone Function

• A ligand is a chemical that attaches to a
  receptor
• Hormones are a category of ligands.
• Hormones can attach to receptors on target cells
  internally or externally.
• Surface receptors are located on the surface of
  the cell.
• Internal receptors are located within a cell.
• Surface receptors rely on bloods watery fluid to
  carry the hormone to the cel membrane.
• If hormone is the correct shape it will attach to
  the receptor on the cell membrane.
• Causes changes within the target cell (effector)

11
Internal receptors and how they work

• Carrier proteins bring hormones to target cells
  (effectors) that use internal receptors.
• One group of carrier proteins is created by the
  liver
• They help to transport these hormones in the
  blood to the cell
• Another group of carrier proteins produced in the
  cell attach the hormone to internal receptors on
  genetic material.
• Transported hormones bind to a special receptor
  that interacts with the DNA
• This interaction either switches on or switches
  off a distinct trait.

12
(No Transcript)
13
Endocrine Secretions

• Autocrine secretions are self governing and
  usually do not travel in the blood. They interact
  with the cell that produced them.
• Paracrine secretions also travel a short distance
  via the blood or body fluid. They signal and
  target cells that are close by.
• Endocrine secretions travel long distance via
  blood. They signal and target cells that are far
  away.
• Pheromones are secretions that leave the body and
  signals the cells of other organisms.

14
Cell Signaling
15
Cell Signaling
16
Negative feedback System

• Most hormones work on a negative feedback system
• Example is the hormone Thyroxine
• Causes increase in metabolic rate. This causes
  body to
• produce heat.
• Thyroxine produced as long as body temperature is
  low.
• Thyroxine shuts its own production off as body
  temperature
• reaches a normal level.
• Thyroxine is not produced unless body temperature
  drops.
• http//highered.mcgraw-hill.com/sites/0072495855/s
  tudent_view0/chapter20/animation__positive_and_neg
  ative_feedback__quiz_1_.html

17
Types of Hormones

• Hormone- any chemical that signals a cell to
  alter its metabolism.
• Agonists- are chemicals that act like hormones.
• Example- foods that contain phytoestrogens act
  like estrogen in the body.
• Antagonists- are chemicals that block the action
  of hormones.
• Many chemical pollutants can interfere with
  hormonal communication because they mimic
  hormones.

18
Types of Hormones

• Two categories of hormones
• Peptide hormones
• Composed of Amino acids
• DNA contains program to build them
• Usually responsible for rapid changes in the body
• Most are involved in short term or immediate
  changes needed
• to regulate metabolism.
• Some have permanent effects on body-ex. GH

19
Types of hormones

• Lipid hormones
• Made from existing lipids in the body or taken in
  through diet.
• Fewer types than peptide hormones
• Valuable role in fluid regulation and sexual
  reproduction
• Two types- hormone-like lipids and steroids.
• Dont travel as easily through the blood
• A carrier molecule secreted into the blood moves
  them
• through the body
• Readily crosses the plasma (cell) membrane.
• Many lipid hormones have long term effects on
  body
• because they directly control DNA.

20
The Endocrine Glands

• The endocrine system is composed of 10 glands.
• Hypothalamus
• Pituitary Gland
• anterior and posterior
• 3. Pineal Gland
• 4. Adrenal Glands
• cortex and medulla
• 5. Thyroid Gland
• 6. Parathyroid Glands
• 7. Pancreas
• 8. Thymus
• 9. Ovaries
• 10. Testes
• http//health.howstuffworks.com/human-body/systems
  /endocrine/adam-200091.htm

21
Endocrine Glands

• Hypothalamus
• Located above the pituitary gland
• Controls the endocrine activity mainly the
  pituitary
• Also controls appetite, body temperature, and
  sleep.
• Pituitary
• Anterior controlled by releasing hormones from
  hypothalamus
• Posterior is under nerve cell control of the
  hypothalamus
• Pineal
• Produces the hormones
• melatonin-involved with regulating body rhythms
• serotonin-involved with appetite, emotions,
  moods and sleep.

22
Endocrine Glands

• Adrenal Glands
• Lie above each kidney
• Two glands fused together
• Adrenal cortex- the outer layer
• Adrenal medulla- the inner layer

• Adrenal Cortex
• Produces Glucocorticosteroids
• Regulate metabolism and inhibit ACTH
• ACTH stimulates the secretion of cortisol
• Cortisol helps metabolize lipids and proteins to
• produce energy
• Produces mineralocorticosteroids
• Regulate the balance of electrolytes and water in
  the body
• Aldosterone is the major mineralcorticosteroid
• It regulates potassium and sodium in the body
• Necessary for muscle and nerve function

23
Endocrine Glands

• Adrenal Glands
• Adrenal medulla
• Produces Adrenaline (Epinephrine)
• Produces Noradrenaline (Norepinephrine)

• What causes the Adrenal glands to produce these
  hormones?
• Heavy physical exertion
• Stress
• Low blood sugar

• What effects do these hormones have on the body?
• Increase the discharge of glucose and fats into
  the blood
• (immediate energy needed to fuel metabolism
• Adrenaline diverts blood away from many of the
• body organs and to muscles.
• fight or flight response
• Elevates the metabolic rate of muscle cells
• Increases blood pressure and heart function
• Noradrenaline affects nerve cell function related
  to the bodys
• response to activity and stress.

24
Endocrine Glands

• Thyroid and Parathyroid glands work together
• Described as paired endocrine glands
• Located just below and in front of the voice box
  in the
• middle of the neck
• Thyroid Gland
• Under control of TSH
• Low body temp and stress prompt release of TSH
• Causes thyroid to release thyroxine
• Thyroxine increases cellular metabolism

• Too much Thyroxine
• Causes accelerated heart rate, fatigue, hair
  loss, light or absent menstrual periods, muscle
  weakness, trembling hands, and weight loss

• Too little Thyroxine
• Causes cold intolerance, constipation, fatigue,
  irritability, memory loss, muscle cramps, and
  weight gain.

25
Endocrine Glands

• Thyroid Gland
• Calcitonin produced by thyroid gland
• Works with parathyroid glands to adjust calcium
  level in blood and bones
• Calcitonin lowers blood calcium
• Encourages retention of calcium in bone

• Parathyroid Gland
• PTH increases the calcium level in the blood by
  removing it from bone tissue
• Stimulates vitamin D production which helps with
  calcium absorption.
• Encourages kidneys to retain calcium and helps
  digestive system to absorb calcium

26
Endocrine Glands

• Pancreas
• Large gland located under the stomach
• Produces digestive enzymes for small intestines
• Produces two hormones from endocrine cell
  clusters (islets)
• Also produces hormones insulin and glucagon
• Islets of Langerhans
• Beta cells produce insulin
• Alpha cells produce glucagon

• Insulin is made
• In response to high glucose levels
• Insulin stimulates the insulin receptors
• This causes the cells to take in the glucose
• Insulin secretion speeds up the conversion of
  glucose into glycogen
• Insulin also causes the body to store unused
  glucose as fat cells.
• Improper insulin function can result in high
  blood glucose levels and cause blood vessel
  decay, dehydration, and kidney damage.

27
Endocrine Glands

• Pancreas
• Glucagon
• Has the opposite role of insulin
• Produced when we have low blood sugar
  (hypoglycemia)
• Encourages the metabolism of fats and proteins
  for energy
• As a way of preserving existing glucose until
  blood sugar levels return to normal.

28
Endocrine Glands
Gonads Ovaries and Testes receive hormones from
the pituitary gland. FSH promotes the formation
of eggs and sperms. LH enables the maturation of
eggs and sperm LH help males produce testosterone
and females produce estrogen and
progesterone. Testes produce testosterone. Ovaries
produce estrogen and progesterone.
29
Sex hormones in Females
Estrogen give females secondary sex
characteristics and also essential for bone
maintenance. Adrenal glands of females are able
to convert steroids into male hormones----androgen
s. It works with estrogen to promote muscle tone
and also cause sex drive in females. Progesterone-
works with estrogen to produce the menstrual
cycle and induce changes during pregnancy.
30
Sex Hormones in Males
Testosterone produces male secondary sex
characteristics ensures sperm maturation respons
ible for muscle development Abuse of anabolic
steroids by athletes they are made up of
chemicals resembling testosterone. High levels
of testosterone can induce brain tumors cause
cardiovascular problems males may be affected by
baldness
31
Pathology of the Endocrine System

• Acromegaly
• due to increase in GH in adulthood
• Results in enlargement of skull, hands, feet,
  tongue
• Abraham Lincoln may have had this.
• Addisons Disease
• decrease in adrenal cortex hormones
• due to malfunction of adrenal glands or pituitary
  gland
• Results in darkening of the skin due to excess
  melanin
• production, dehydration, low blood pressure, low
  blood
• sugar, and sodium loss.
• Cushings syndrome
• Due to overproduction of adrenal cortex hormone
• due to malfunction or tumor of adrenal glands or
• Excess of ACTH secretions.

32
Pathology of the Endocrine System
Diabetes Insipidus Inadequate amount of
ADH Produces extreme water loss due to frequent
urination. Diabetes Mellitus Caused by decreased
insulin production (Type I) or Bodys inability
to detect insulin signals (Type II) Results in
high blood sugar and a variety of disorders due
to abnormal glucose levels Can lead
to blindness, blood vessel destruction, kidney
failure
33
Pathology of the Endocrine System
Hyperparathyroidism Overproduction of
parathyroid hormone Caused by immune system
disorders, kidney diseases, parathyroid tumors,
pregnancy Produces elevated calcium levels,
therefore calcium loss from bones. Results in
kidney problems and weakening of
bones Hypothyroidism Thyroid gland does not
produce enough thyroxine In children it results
in mental retardation and short stature In
adults it causes lethargy, weight gain, dry hair
and skin, and sensitivity to cold.
34
Pathology of the Endocrine System
Graves Disease (hyperthyroidism) caused by
inflammation of thyroid gland due to elevated
thyroid hormone. Caused by an autoimmune
disease Results in elevated metabolic rate and
feelings of nervousness or tension.