Chapter 26: Reproductive Systems. Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2 Lesson 26.1 Objectives List the structures

Chapter 26:

Reproductive Systems

Copyright © 2007 by Saunders, an imprint of Elsevier Inc.

All rights reserved.

2

Lesson 26.1 Objectives

List the structures and functions of the male and female reproductive systems.

Describe the structure and function of the testes.

Describe the structure and function of the male genital ducts.



3

Lesson 26.1 Objectives (cont’d.)

Describe the accessory glands that add secretions to the semen.

Describe the hormonal control of male reproduction, including the effects of testosterone.



4

Reproductive Systems

Functions of the reproductive systems:Produce, nurture, and transport ova

and spermSecrete hormones

Reproduction is sexual- meaning that both a female and male partner are required for reproduction

5

Reproductive Systems (cont’d.)

Reproductive organs: Primary reproductive organs: gonads

• Female gonads: ovaries• Male gonads: testes• The functions of the gonads are to secrete hormones and

produce gametes (eggs and sperms)

Secondary reproductive organs: all other organs, ducts, and glands in the reproductive system

• Function is to nourish and transport the eggs and sperm• Female secondary structures provide a safe, nurturing

environment for the fertilized egg



6

Male Reproductive System

Roles of the male reproductive system:Produce, nourish, and transport spermDeposit sperm within the female

reproductive tractSecrete hormones

7

Male Reproductive System (cont’d.)

Testes: testicles; male gonads 2 functions- produce sperm and secrete testosterone Located outside of the abdominal cavity in the

scrotum Testosterone: male hormone Lobules: smaller units of the testis

Approx. 250 lobules in each testis Contains interstitial cells (produce androgens)and

seminiferous tubules (produce sperm) Androgens: male hormones, including testosterone

8

Pathway of sperm



9


Spermatogenesis: formation of sperm Most sperm live only a few hours; some may

survive up to 3 days Spermatogonia: undifferentiated spermatogenic

cells Meiosis: special type of cell division; reduces the

number of chromosomes from 46 to 23 in the primary spermatocytes

Each sperm has only 23 chromosomes same as each egg; when they unite, they form a zygote with 46 chromosomes

10

11


Genital ducts: Epididymis: first part of the duct system; located along

the top and posterior side of the testis (about 20 feet long); sperm mature and become motile

Vas deferens: continuous with the epididymis; curves over the urinary bladder and joins the duct of the seminal vesicle to form the ejaculatory duct

Ejaculatory ducts: pass through the prostate gland and join with the urethra

Urethra: extends from the base of the urinary bladder to the tip of the penis; part of the reproductive and urinary system; never passes urine and semen at the same time



12


The pathway for semen.

13


Accessory glands: (as the sperm travel through the ducts various secretions are added) Seminal vesicles: located at the base of the bladder;

secrete a thick, yellowish material (rich in fructose, vitamin C and prostaglandins which nourish and activate the sperm)

Prostate gland: encircles the upper urethra just below the bladder; secretes a milky, alkaline substance (increases sperm motility and helps neutralize the acidic secretions of the vagina)

Bulbourethral glands (Cowper’s glands): tiny glands that secrete thick mucus into the urethra; serves as a lubricant

14


Semen: mixture of sperm and the secretions of the accessory glands The amount of semen secreted is only about 2 to

6ml, but contains 50 to 100 million sperm External genitals: scrotum and penis Scrotum: sac that hangs between the legs and

contains the testes; helps to regulate temperature Penis: carries urine through the urethra to the

outside of the body and deposits sperm in the female reproductive tract; contains erectile tissue and is considered the organ of copulation



15


Glans penis: the enlarged tip of the penis covered with loose fold of skin called the

prepuce, or foreskin Erection: accumulation of blood in the

erectile tissue causing the penis to enlarge and become rigid

Orgasm: pleasurable sensations that occur at the height of sexual stimulation Accompanied by emission and ejaculation



16


Emission: movement of sperm and glandular secretions from the testes and genital ducts into the proximal urethra Up: Erection—parasympathetic nervous

system Out: Emission—sympathetic nervous system

Ejaculation: expulsion of semen from the urethra to the outside Up: Erect—parasympathetic nervous system Down: Flaccid—sympathetic nervous system



17

Lesson 26.2 Objectives

Describe the structure and function of the ovaries.

Describe the structure and function of the female genital tract.

Explain the hormonal control of the female reproductive cycle.



18

Female Reproductive System

Three roles:Produce eggsSecrete hormonesNurture and protect a developing baby during

the nine months of pregnancy

Female Reproductive System (cont’d.)

Ovaries: female gonadsFound on either side of the uterus; close to

the fallopian tubes, held in place by ovarian and broad ligaments

Ovarian follicles: tiny saclike structures within the ovary (born with approx. 2 million)

Oocyte: immature egg Follicular cells: cells surrounding the oocyte in the

ovarian follicle Graafian follicle: mature ovarian follicle Ovum: mature egg

22



23


Ovulation: ejection phase of a mature eggOccurs approximately once per month

Fimbriae: fingerlike projections at the end of the fallopian tubes; perform swishing motion to sweep the ovum into the fallopian tubes

Corpus luteum: glandular structure developed by follicular cells that remain in the ovary after ovulation

Corpus albicans: deteriorated corpus luteum



24


Effects of estrogen: Promotes the maturation of the eggsHelps develop the female secondary sex

characteristics• Enlargement and development of the organs of the

female reproductive system• Enlargement and development of the breasts• Deposition of fat beneath the skin• Widening of the pelvis• Onset of menstruation• Closure of the epiphyseal discs in long bones



25


Effects of progesterone:Works with estrogen in establishing the

menstrual cycleHelps maintain pregnancyPrepares the breasts for milk production after

pregnancy



26


Fallopian tubes Extend from either side of the uterus to the ovaries (also

called the uterine tubes or oviducts) Infundibulum: funnel-shaped end nearest the ovary Has finger-like projections called fimbrae that hang over

the ovary and sweep the egg from the surface of the ovary into the fallopian tube

Peristalsis moves the egg along the fallopian tube toward the uterus; the fallopian tube is the usual site of fertilization of the egg by the sperm

27


Uterus: Shaped like an upside-down pear; located between the

urinary bladder and the rectum Held in place by broad ligaments Three layers include epimetrium (perimetrium),

myometrium and endometrium Parts of the uterus

• Fundus: upper dome-shaped region above the entrance to the fallopian tubes

• Body: central region• Cervix: lower narrow region; opens into the vagina



28


VaginaExtends from the cervix to the vaginal opening

in the perineum• Hymen: thin membrane covering the vaginal opening• Fornices: pockets that form in the vagina around the

cervix

29



30


Vulva: external genitals Labia majora: folds of hair-covered skin that lie external

to the labia minora Labia minora: inner folds of skin separated by a cleft

containing the urethral and vaginal openings Clitoris: contains sensory receptors that allow the

female to experience sexual sensations; contains erectile tissue- similar to the penis

Vestibular glands: secrete a a mucus-containing substance; lie on either side of the vaginal opening



31

Methods of Birth Control

Birth control: voluntary regulation of reproduction Barrier method: prevents the sperm from entering

the female Hormonal contraceptives (e.g., the Pill): prevent

ovulation by maintaining hormone levels Surgical methods: vasectomy and tubal ligation Intrauterine device: prevents implantation Behavioral methods: abstinence, the rhythm method,

and coitus interruptus Emergency contraception: prevents ovulation and

inhibits implantation or causes endometrium to slough



32

Methods of Birth Control (cont’d.)

Two methods of tubal ligation

Types of Birth Control

Documents

Chapter 26: Reproductive Systems. Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2 Lesson 26.1 Objectives List the structures