chapter 9 part a

The Endocrine System

Chapter 9

1.     Overview

a.    Second control system

b.    Chemical messengers- uses chemical messengers(hormones); released into the blood: usually long term control

c.    Hormones control several major processes- reproduction, growth and development, mobilization of body defenses, maintenance of much of homeostasis, regulation of metabolism.

2.    Hormones

a.    Overview

                                          i.    Hormones produced by specialized cells.

                                        ii.    Cells secrete hormones into extracellular fluids.

                                       iii.    Blood transfers hormones to target sites.

                                       iv.    Specific effects- these hormones have specific effects on these cells.

b.    Chemistry – hormones classified as: amino acid/ protein based, steroids-made from cholesterol, prostaglandins- made from highly active lipids.

c.    Mechanism of action

                                          i.    Target cells, tissues, or organs- hormones affect only certain tissues or organs. Target cells must have specific protein receptors

                                        ii.    Hormone binding alters cellular activity

                                       iii.    Direct gene action

1.     Diffuse through the plasma membrane of target cells

2.    Enter the nucleus

3.    Bind to a specific protein within the nucleus, bind to specific sites on cell’s DNA

4.    Activate genes that result in synthesis of new proteins

                                       iv.    Second messenger system(indirect); the hormone:

1.     Binds to a membrane receptor

2.    Does not enter the cell

3.    Sets off a series of reactions that activates an enzyme

4.    Catalyzes a reaction that produces a second-messenger molecule

5.    Oversees additional intracellular changes to promote a specific response

                                         v.    How hormone release is controlled

1.     Levels in the blood are mostly maintained by negative feedback

2.    Stops when an appropriate level in the blood is reached

a.    Release triggered by  

b.    Levels of other hormones

c.    Levels of certain ions in the blood

d.    Nerve impulses usually sympathetic nervous system

3.    Overview of the system

a.    Spread throughout the body

b.    Sometimes part of other systems

c.    List of major organs

4.    Pituitary gland= master gland

a.    Size- pea

b.    Hangs from the hypothalamus in the brain

c.    Protected by the sphenoid bone

d.    Two functional lobes- anterior pituitary- glandular tissue, posterior pituitary- nervous tissue.

e.    Referred to as- the master gland

f.    Anterior pituitary hormones- 6 pituitary hormones

                                          i.    Targets are non-endocrine- 2 non-endocrine targets

1.     GH = growth hormone

2.    PRL = prolactin

                                        ii.    Tropic hormones: affect other endocrine glands- 4 tropic hormones

1.     TSH = thyroid stimulating hormone (thyrotropic hormone)

2.    ACTH = adrenocorticotropic hormone

3.    Gonadotropins-2

a.    FSH =

b.    LH =

5.    Hormones of the anterior pituitary

a.    Growth hormone

                                          i.    General metabolic hormone

                                        ii.    Major effects are directed to growth of skeletal muscles and long bones

                                       iii.    Plays a role in determining final body size

                                       iv.    Causes amino acids to be built into proteins, and causes fats to be broken down for source of energy

                                         v.    Disorders

1.     Pituitary dwarfism results from hyposecretion of GH during childhood

2.    Gigantism results from hypersecretion of GH during childhood

3.    Acromegaly results from hypersecretion of GH during adulthood

b.    Prolactin

                                          i.    In women it stimulates and maintains milk production following childbirth

                                        ii.    In men function is unknown

c.    Adrenocorticotropic hormone(ACTH)

                                          i.    Regulates endocrine activity of the adrenal cortex

d.    Thyroid-stimulating hormone(TSH)

                                          i.    Influences growth and activity of the thyroid gland

e.    Gonadotropins regulate hormonal activity of the glands

                                          i.    Follicle-stimulating hormone(FSH)

1.     In ovaries stimulates follicle(egg)  development in ovaries

2.    In testes stimulates sperm development in testes

                                        ii.    Luteinizing hormone(LH)

1.     In females triggers ovulation of an egg in females

2.    In males stimulates testosterone production in males

6.    Pituitary/hypothalamus relationship-hormonal release is regulated by releasing and inhibiting hormones produced by the hypothalamus

a.    Hypothalamus hormones produces two hormones transported to the posterior pituitary

                                          i.    Oxytosin

1.     Stimulates contractions of the uterus during labor, sexual relations, and breastfeeding

2.    Causes milk ejection in a nursing woman

                                        ii.    Antidiuretic hormone(ADH)

1.     Inhibits urine production by promoting water reabsorption by the kidneys

2.    Causes vasoconstriction leading to increased blood pressure

3.    AKA vasopressin

                                       iii.    Transported to posterior pituitary via

chapter 16 part c

Chapter 16: Reproductive System & Development

Part C: Menstrual cycle, Pregnancy

1.     Menstrual (uterine) cycle

a.    Overview

                                          i.    Cyclic changes of the endometrium

                                        ii.    Regulated by cyclic production of estrogen and progesterone

                                       iii.    FSH and LH regulate the production of estrogen and progesterone

                                       iv.    Both female cycles are about 28 days in length

                                         v.    Ovulation typically occurs about midway through cycle on day 14

1.     However, there are a lot of variations

b.    Stages

                                          i.    Menstrual phase

1.     Days 1-5

2.    Functional layer of the endometrium is sloughed

3.    Bleeding occurs for 3-5 days

4.    By day 5, growing ovarian follicles are producing more estrogen

                                        ii.    Proliferative stage

1.     Days 6-14

2.    Regulation of functional layer of the endometrium

3.    Estrogen levels rise

4.    Ovulation occurs  in the ovary at the end of this stage

                                       iii.    Secretory stage

1.     Days 15-28

2.    Progesterone levels rise and increase the blood supply to the endometrium

3.    Endometrium  increases in size and readies for implantation

4.    If fertilization does occur:

5.    Embryo produces a hormone(HCG) that causes the corpus lutem to continue producing its hormone

a.    If fertilization does not occur:

b.    Corpus luteum degenerates as LH blood levels decline

c.    Hormones produced by ovaries

                                          i.    Estrogen

1.     Produced by follicle cells

2.    Cause secondary sex characteristics:

a.    Enlargement of accessory organs

b.    Development of breasts

c.    Appearance of axillary and pubic hair

d.    Increase in  fat beneath the skin, particularly in hips and breasts

e.    Widening and lightening of the pelvis

f.    Onset of menses (menstrual cycle)

                                        ii.    Progesterone = the hormone of pregnancy

1.     Produced by the corpus luteum

2.    Production continues until LH diminishes in the blood

3.    Does not contribute  to the appearance of secondary sex characteristics

4.    Helps maintain pregnancy

5.    Prepares breasts for milk production

6.    Feedback

d.    Mammary glands

                                          i.    Present in

1.     Modified

                                        ii.    Function is

                                       iii.    Stimulated by

chapter 16 part b

Chapter 16: Reproductive System

Part B: Female System

1.     Overview

a.    Ovaries (2)—produce eggs and female sex hormones

b.    Duct system: (transportation)

                                          i.    Fallopian tubes (2)—egg transport

                                        ii.    Uterus (1)—embryo/fetal development

                                       iii.    Vagina (1)—copulation, birth canal

c.    External genitalia—copulation

2.    Ovaries

a.    Composed of ovarian follicles (sac-like structures):

                                          i.    Oocyte (immature egg)

                                        ii.    Follicular cells—surround the oocyte

                                       iii.    Follicular stages

1.     Primary follicle—contains an immature oocyte

2.    Graafian (vesicular) follicle—growing follicle with a maturing oocyte

3.    Ovulation—when the egg is mature, the follicle ruptures (about every 28 days).

4.    The ruptured follilcle is transformed into a Corpus luteum

b.    Support

                                          i.    Suspensory ligaments—secure ovary to lateral walls of the pelvis

                                        ii.    Ovarian ligaments—attach to uterus

                                       iii.    Broad ligament—a fold of the peritoneum, encloses suspensory ligament

3.    Duct system

a.    Fallopian tubes(uterine tubes)

                                          i.    Receive the ovulated oocyte

                                        ii.    Provide a site for fertilization

                                       iii.    Attach  to the uterus

                                       iv.    Little or no contact between the ovaries and uterine tubes

                                         v.    Supported and enclosed by the broad ligament

                                       vi.    Anatomy & physiology

1.     Fimbriae

a.    Finger-like projections at the distal end of the uterine tube

b.    Receive  the oocyte from the ovary

2.    Cilia

a.    Located inside the uterine tube

b.    Slowly move the oocyte towards the uterus (takes 3-4 days)

3.    Fertilization occurs inside the uterine tube since oocyte lives about 24 hours

b.    Uterus

                                          i.    Located between the urinary bladder and rectum

                                        ii.    Hollow organ- pear shaped

                                       iii.    Functions

1.     Receives fertilized eggs

2.    Retains the fertilized egg

3.    Nourishes  the fertilized egg

                                       iv.    Support

1.     Broad

2.    Round

3.    Uterosacral

                                         v.    Regions of

1.     Body –main portion

2.    Fundus- superior rounded region above where uterine tube enters

3.    Cervix- narrow outlet that protrudes into the vagina

                                       vi.    Walls of

1.     Endometrium

a.    Inner layer

b.    Allows for implantation of fertilized egg

c.    Sloughs off if no pregnancy occurs ( menses)

2.    Myometrium- middle layer of smooth muscle

3.    Perimetrium (visceral peritoneum)- outermost serous layer of the uterus

c.    Vagina

                                          i.    Extends from

                                        ii.    Located between

                                       iii.    Serves as

                                       iv.    Receives

                                         v.    Hymen

4.    External genitalia = vulva

a.    Mons pubis

                                          i.    Fatty area

                                        ii.    Covered with

b.    Labia =

                                          i.    Majora

                                        ii.    Minora

                                       iii.    Corresponds to

                                       iv.    Majora encloses vestibule

1.     Contains external openings of

c.    Clitoris

                                          i.    Contains

                                        ii.    Corresponds to

1.     Hooded

2.    Composed of

3.    Becomes swollen

d.    Greater vestibular glands

                                          i.    One found on

                                        ii.    Secretes

e.    Perineum

                                          i.    Diamond-shaped defined by:

1.     Anterior:

2.    Posterior:

3.    Lateral:

                                        ii.    Urethral orifice

                                       iii.    Vaginal orifice

5.    Oogenesis and ovarian cycle

a.    Total supply of eggs are present at birth

b.    Ability to release eggs begins at puberty

c.    Reproductive ability ends at menopause

d.    Oocytes are matured in developing ovarian follicles

e.    The process and steps of oogenesis

                                          i.    Oogonia—female stem cells found in a developing fetus

                                        ii.    Oogonia undergo mitosis to produce primary oocytes

                                       iii.    Cells surrounding primary oocytes that form primary follicles in the ovary

                                       iv.    Oogonia no longer exist by the time of birth

                                         v.    Primary oocytes are inactive until puberty

                                       vi.    Follicle stimulating hormone (FSH) causes some primary follicles to mature each month

                                      vii.    Cyclic monthly changes constitute the ovarian cycle

f.    Meiosis

                                          i.    Starts inside maturing follicle

                                        ii.    Produces a secondary oocyte and the first polar body

                                       iii.    Development to mature stage takes about 14 days

                                       iv.    Secondary oocyte ovulates with the release of luteinizing hormone (LH).

1.     Surrounded by a corona radiate (nurturing cells)

                                         v.    Is completed

1.     Ovum = egg

2.    Two additional

                                       vi.    Zygote (fertilized egg) =

                                      vii.    If no fertilization

                                     viii.    Comparison

1.     Males

2.    Females

                                       ix.    Sperm and egg comparison

1.     Sperm

2.    Egg