Chapter 27

1. Produce gametes

2. Mechanism for gametes to come together (intercourse)

3. Genetic material combines

4. Mechanism to support fetus during gestation and birth

Four requirements for successful reproduction:

Testes

Sperm producing male gonads that lie within the scrotum. Has two lobes.

1. Created in seminierous tubules that

2. feeds into straight tubules

3. goes to rete testes

4. to efferent ductules

5. Epididymis

Pathway of sperm from testes to epididymis: [5]

Seminiferous tubules

Yellow tubes where sperm are created.

Tail of epididymis

Where are sperm stored until required for ejaculation?

Spermatic cord

Contains arteries, veins, verve fibers, and lymphatics hat supply testes. Encased on connective tissue sheath. Supplies rich blood and nerves (autonomic) to testes.

Scrotum

Houses paired testes. Outside the body, where temperature is 3 degrees lower (essential for sperm production and survival)

1. They get pulled closer to the warm body so that temperature is optimal for sperm. Muscles change position and location of the testes to maintain optimal temperature.

2. skin wrinkles to decrease surface area for loss of heat.

What happens when testes are cold? [2]

PENIS

Male copulatory organ, delivers sperm into female reproductive tract

1. Scrotum

2. penis

Male external genetalia (collectively): [2]

1. Root of penis

2. Body of penis

3. Glans penis

Three parts of the penis from proximal to distal:

Prepuce, or foreskin

Loose skin that forms a cuff distally on the penis:

Spongy urethra

How urine and sperm travel outside the body

Cylindrical bodies [3]

Columns that are filled with smooth muscle and vascular spaces in the penis. Rich blood supply, tissues fill with blood that cause penis to enlarge and become rigid during sexual excitement.

Corpus spongiosum

Smaller cylindrical body. Houses and protects spongy urethra.

Corpora cavernosa

Two larger cylindrical bodies

1. Scrotum attaches

2. Root of penis

3. Anus

4. Pubic symphysis

5. Coccyx

6. Ischial tuberosities

7. Whole floor are pelvic floor muscles

Male perineum contains: [7]

1. Seminal glands/ seminal vesicles

2. Prostate

3. Bulbo-urethral glands

Three main male accessory glands

Seminal glands

Male accessory glands that lie posterior to the bladder. Produces secretions that make 70% of semen volume. When secretions are produced, there is a duct that ultimately joins ejaculatory duct.

Prostate

Muscular structure with lots of connective tissue that surrounds urethra. Squeezes prostatic secretions into urethra during ejaculation. Plays an important role in activating sperm.

Bulbo-urethral glands

Paired glands that produce thick mucous that lubricates glans penis when male is sexually excited (not related to semen specifically)

Semen

Milky white, sticky mixture of gland secretions and sperm.

1. Transportation medium for sperm

2. Provides nutrients to living sperm cells

3. Contains chemical that protects and activates sperm and facilitates their movement

Functions of accessory gland secretions: [3]

Prostaglandins

Chemical messengers in semen that make it easier for sperm to enter uterus by thinning mucous in cervix

Hormone relaxin

Hormone in semen that enhances sperm motility, so they can move quicker and more effeciently

Provide sperm with energy to move

Function of ATP in semen:

So that the sperm is not targeted and destroyed by female immune system

Why is there an ingredient in sperm that suppresses the female immune response?

1. Clotting factors cause semen to clot just after ejaculation so that it sticks to the walls of the vagina.

2. Without it, semen out run out of the vagina and not fertilize the egg

3. Soon after coagulation, enzymes reverse the process once sperm are safely inside

Describe semen coagulation process:

1. Erection: allows for penetration (parasympathetic)

2. Ejaculation: expels sperm into the vagina (sympathetic)

Phases of the male sexual response: [2]

1. Engorgement of erectile bodies with blood

2. Sexual excitement causes CNS to activate parasympathetic nervous system

3. Relaxaion of smooth muscles

4. Arterioles dilate

5. Stops veinous drainage; puts pressure on veins so no blood can leave

erection of the penis results from what? [5]

Keeps urethra open. If it filled with blood, urethra would collapse. Semen needs to get through

Role of corpus spongiosum during erection:

Ejaculation

Propulsion of semen from duct system

1. Ducts contract and empty contents into prostatic urethra

2. Internal sphincter of bladder constricts

3. Muscles of penis undergo rapid contractions that cause expulsion of semen

Three things that happen when an erection triggers spinal reflex [3]

Climax

Ejaculatory event accompanied by intense pleasure, increased heart rate and blood pressure

Spermatogenesis

Creation of sperm

Seminiferous tubules in testes

Where does spermatogenesis happen

Begins at puberty (around 14) and continues throughout the lifetime

When does spermatogenesis begin and end

Testosterone

Production of sperm is initiated by which ormone?

Spermatogonium

Starting point for spermatogenesis (stem cell)

1. starting point: spermatogonium

2. After puberty, starts to divide

3. Ultimately produces sperocytes

4. These ultimately become speratids

5. Which ultimately become sperm

Spermatogenesis at level of detail we need to know for this course:

1. Head

2. Midpiece

3. tail

Three major regions of sperm cells

Head

Region of sperm that carries genetic code in nucleus. Also has acromion “helmet” that contains enzymes to penetrate the egg

Midpiece

Region of the sperm that contains mitochondria, enables the tail to move

TailThr

Locomotor region of sperm cells. Enables sperm to swim

1. Hypothalamus

2. Anterior pituitary

3. Gonads

Three places hormones come from in male and female repdocutive systems:

HPG (hypothalamic pituitary gonadal) axis

Relationship between all reproductive hormones inmales and females. Name given to the structures and the hormones they release

GnRH

Hormone released by the hypothalamus that can be triggered for many reasons. Travels in blood and acts as a humoral stimulus on anterior pituitary.

1. LH

2. FSH

GnRH stimulates anterior pituitary to release what hormones? [2]

Stimulate gonads to release sex hormone

Generally, what do LH and FSH do in body?

Testosterone

Steroid hormone that is made cholesterol. Male sex hormone that acts on target cells.

Negative feedback loop

Inhibitory stimuli happening as well, feedback loop that inhibits something from happening.

1. Once testosterone is released, hypothalamus inhibits GnRH release

2. Anterior pituitary has inhibitory effect

3. Ensures we don’t have too much sex hormone releas

4. Hormone inhibin is released from gonads

5. Inhibits hormone release from hypothalamus and anterior pituirary

Describe negative feedback loop for sex hormones in males:

Stimulates testes to produce testosterone

What does LH stimulate (males)?

Stimulates testes to produce sperm

What does FSH stimulate (males)?

1. Stimulates growth and maturation of male reproductive system

2. Secondary sex characteristics

3. Increased size and density of bone

4. Basal metabolic rate increases

5. Basis of male sex drive

Rising levels of testosterone at puberty stimulate what?

At fertilization, there is a need for prenatal secretion of testosterone

Why are fetal testosterone levels higher ?

Ovaries

female gonads. Paired structures held in place by ligaments that produce female gametes and secrete female sex hormones:

1. estrogen

2. Progesterone

Female sex hormones: [2]

internal genitalia

1. ovaries

2. duct system

3. uterus

4. vagina

Female genitalia located within the pelvic cavity [4]

They develop in ovarian follicles within the ovares.

Where do female gametes develop?

Ovarian follicles

sac-like structures inside the ovaries that contain immature eggs

Oocyte

Immature eggs within immature follicles in ovaries

Each month, a few et selected. One of the mature follicles releases an egg during ovulation

Follicles stay dormant until when?

Ovulation

Ejection of oocyte from a mature follicle

Develops into corpus luteum, produces high levels of estrogen and progesterone

Once ovulation happens, what happens to the follicle?

1. ovary is not directly connected to tubes.

2. Oocyte is released into the peritoneal cavity

3. The end of the fallopian tube has finger-like projections

4. Creates a current to encourage oocyte to flow into fallopian tube

5. Once in tube, travels via peristalsis and ciliary action

How does egg get from ovary to uterus

1. uterine tubes

2. uterus

3. vagina

female tube system includes

infundibulum

expansion near the ovary, contains fimbriae that create current to move oocyte into uterine tube (distal end of uterine tube)

Ectopic pregnancy

When an egg is fertilized in peritoneal cavity or distal uterine tube and begins developing there. Normally aborts naturally with substantial bleeding.

uterus

Hollow, thick-walled organ that is in pelvic cavity that receives, retains, and nourishes a fertilized egg

1. Body

2. Fundus

3. Isthmus

4. Cervix

Three main regions of the uterus

Body

Main portion of the uterus

Fundus

Rounded superior region of the uterus

Isthmus

Narrowed inferior region of the uterus:

Cervix

Part of uterus that projects into the vagina

Is not floating. Flexible ligaments allow it to move as bladder and rectum fill and empty

How is uterus anchored in place?

3

How many layers does the uterus have?

1. functional layer

2. Basal layer

Two layers of the endometrium:

Functional layer

Layer of endometrium that is shed during menstruation, gets established to prepare inner wall of uterus to house fertalized egg

Basal layer

Layer of endometrium that is made up of stem cells. Can form a new functional layer monthly

1. organ of copulation

2. Birth canal

3. path for menstrual flow

Three functions of vagina: [3]

1. outer fibrous layer

2. smooth muscle laer

3. inner mucosa

Three layers of the vagina:

Inner mucosa is lubricated by cervical mucosa glands

How is vagina lubricated?

Hymen

Incomplete partition over vaginal open, found in women who have not had sexual intercourse

External genitalia, also called vulva

refers to the female reproductive structures that lie external to the vagina.

1. Mons pubis

2. Labia

3. Clitoris

4. Structures associated with vestibule

External genitals include: (female)[4]

Clitoris

Erectile tissue in reproductive system

vestibule

Contains external opening of urethra and vagina, and greater vestibular glands

Greater vestibular glands

Glands that secrete mucous into vestibule to keep moist for intercourse

Milk production to nourish newborn

Main function of mammary glands

Mammary glands

Modified sweat glands consisting of 15-25 lobes

Lobules

Contains glandular alveoli that produce milk

Suspensory ligaments, firmly attach to pectoral muscle.

How are mammary glands held in place?

oogenesis

Creation of female gametes

Oogonia

Female sex stem cells

Before birth. Eggs in follicles are inactive and not capable of producing life. Primary oocytes exist in a follicle

When does process of oogenesis start?

Programmed cell death

What happens to primary oocytes prior to puberty?

Meiosis

Process by which gametes are made. Begins before puberty.

Primary oocyte undergoes meiosis, becomes secondary oocyte. meiosis stops.

Ovulation happens

Won’t become an egg until sperm fertalizes it

Once fertalized, quickly starts and stops to produce ova

What happens once a follicle is chosen?

1. follicular phase

2. luteal phase

Two phases of the ovarian cycle