1 The Urinary and Reproductive Systems Lab 12—7-11 Excretion refers to the processes that remove wastes and excess materials from the body. Urine is essentially

1

The Urinary and Reproductive Systems Lab 12—7-11

• Excretion refers to the processes that remove wastes and excess materials from the body.

• Urine is essentially water and solutes.– Some of the solutes excreted in urine are:• excess elements, drugs, vitamins, toxic

chemicals, waste produced by the liver and cellular metabolism, salt

2

The Urinary and Reproductive SystemsLab 12

• The urinary system is composed of the organs that produce, transport, store and excrete urine:–2 kidneys, 2 ureters, one bladder and one

urethra• The Kidneys– are bean shaped organs about the size of a

clenched fist

3


– are located in the abdominal cavity*, lateral to the 2nd lumbar vertebrae and close to the posterior wall of the body (our back).

*some people believe the kidneys are located retroperitoneally (behind the abdominal cavity lining and part of the posterior body wall)– a renal artery and vein connect each kidney

to the aorta and inferior vena cava.

4


Gross anatomy of the kidneys:• the capsule is the protective outer covering of

the kidney• the interior of the kidney has 2 distinct areas:

the cortex and the medulla• the cortex is the outer portion. It has most of

the capillary blood flow, and contains the renal corpuscles, which contain the nephrons, the functional unit of the kidney .

5

The Urinary and Reproductive Systems Lab 12

– The nephron is the functional unit of the kidney. It is divided into several different areas: • the glomerular or Bowman’s capsule which

surrounds the glomerulus, • the proximal convoluted tubule (a thin

hollow tube of epithelial cells), • loop of Henle, composed of a descending

tubule, a loop, and an ascending tubule• distal convoluted tubule, • collecting tubule• blood vessels that supply the tubules,

6


• How a Nephron works to produce urine:• The glomerular capsule surrounds the

glomerulus which is a network of capillaries.– blood plasma fluid is filtered out of the capillaries and

into the space between the 2 layers of the glomerular capsule

• A tubule exits from the back of the glomerular capsule and continues as a long, thin tube with 4 distinct regions: – the proximal tubule– The loop of Henle

7


– the distal convoluted tubule– The collecting duct - up to 1,000 distal

tubules can join together to become a collecting duct– The collecting duct leads into the renal

pelvis where the final urine is deposited.

8


• The kidney medulla is composed of cone shaped pyramids. The base of each pyramid faces toward the cortex and the point faces toward the middle of our body. – The pyramids appear striped because

they are formed of parallel bundles of microscopic urine collecting tubules, the loop of Henle and the collecting ducts.

9


• The tips of the pyramids are called the papillae. These insert into the opening of a tube called the calyx.• Filtered urine is transported to the

kidney pelvis, the innermost hollow, muscular part of the kidney.• The pelvis empties into the ureters.

10


• The smooth muscle of the ureters create peristaltic waves which move the urine into the bladder.– The bladder can usually hold between 2-3.5 ounces. – Women typically have smaller bladder capacity than

men because the uterus compresses the bladder.• The external and internal urethral sphincter

prevent the bladder from emptying until we are ready to do so.

• During urination, urine passes into the urethra, a muscular tube that extends from the bladder to the body’s opening.

11

The Urinary and Reproductive Systems Blood vessels and filtration

How does the kidney filter our blood?• Blood enters the interlobular artery. This

branches into afferent arterioles which enter the glomerular capsule where they divide many times to become the network of capillaries that make up the glomerulus.

• The blood pressure in the glomerular capsule is high in order to allow filtration of plasma fluid and solutes from the blood into the capsular space.

12


• The filtered material is called the glomerular filtrate. It contains urea, amino acids, vitamins, hormones, salts, glucose, ions and water, but no large proteins or blood cells.

• Reabsorption of water, glucose, amino acids, hormones, ions, vitamins and some salts occurs mainly in the walls of the proximal convoluted tubule. – Approximately 65% of water is reabsorbed here.

13


• The Loop of Henle and the Distal Convoluted Tubule also perform reabsorption and secretion of ions.– Tubular excretion or secretion refers to the process in which cells

in the proximal and distal tubules pass materials into and remove substances from the filtrate.

• The Collecting Tubule or Duct receives filtrate from several distal convoluted tubules and empties into the calyces and pelvis. Some reabsorption and secretion, especially ions and urea, may occur. – Regulation of water reabsorption happens

here.

14


• An important pituitary hormone, the anti-diuretic hormone (ADH) regulates the reabsorption of water in the kidney tubules.–Diuretics are substances that increase

the flow of urine.

15


• The kidney reabsorbs water and ions and thus prevents the loss of substances which the body needs. It adjusts the composition of blood and body fluids through this filtration process.

• Urine is the final product of the filtration process. It leaves the distal tubules, empties into the renal pelvis and then travels through the ureters to the bladder.

• From the bladder, it goes into the urethra and then exits the body when we choose to urinate.

16

REMINDER, page 1 of 2: Urinary System

1. Using figures 16.1 and 16.2 as a guide, learn parts of the urinary system on the model.

2. In the fetal pig, find the kidneys, ureters, and urinary bladder.

3. On the SHEEP kidney, identify the bulleted items listed on page 153.

4. 4. Do the urine hydrometer and Combistix test. In the hydrometer we actually have yellow food color,

water, and other “stuff” to approximate urine. The yellow food color may stain so don’t spill it on yourself.

17

Lab 12

REMINDER, page 2 of 2: Urinary System

– The more solute in urine, the more buoyant it is (like swimming in salt vs fresh water). The more concentrated urine is, the higher the hydrometer will float.– The hydrometer is no longer used in

doctors' offices; a dipstick test is used now.

5. Observe the kidney stones in the jar.

18

Lab 12 The Urinary and Reproductive Systems

The Reproductive Systems-Male• The term genitalia refers to reproductive organs.Anatomy of the Male Reproductive System

look at picture on page 161

• The scrotal sac contains 2 testes which produce sperm (the male reproductive cells).– The testes are located outside of the body

because sperm need lower temperatures to survive.

• The seminiferous tubules, in the testes produce sperm.

Sperm• Consist of 3 major parts: a head, midpiece, and a

tail• The head contains the nucleus and ½ the number

of chromosomes of the parent• The midpiece contains mitochondria and ATP

which produce the energy to power the tail• The tail propels the sperm• The process of sperm formation is called

spermatogenesis.

19

20


• In between the seminiferous tubules are interstitial cells which produce testosterone, the male hormone.

• Sperm production involves a series of cell divisions called meiosis and produces sperm with ½ the number of chromosomes of the parent

• Many seminiferous tubules join to become the epididymus which is located at the rear of the testes. Sperm are stored here.

• They enter the vas deferens (the sperm duct) which passes through an opening in the wall of the body called the inguinal canal.

21


– The ability of newly formed sperm to swim develops in both the epididymis and the vas deferens.

– A vasectomy ties off the vas deferens so sperm are no longer available for fertilization.

• The vas deferens connects to the ejaculatory duct.

• When the male ejaculates semen, rhythmic contractions of smooth muscle propel the sperm through the ejaculatory duct and then through the urethra.

22


• The penis is the male organ of sexual intercourse. It contains erectile tissue that fills with blood and causes the erection during sexual stimulation.

23


Glands which help sperm survive:• Prostate gland: surrounds the urethra and

produces an alkaline fluid which is added to the seminal fluid. This raises the pH of the vagina to a more optimal pH for sperm survival.

• Seminal vesicles produce seminal fluid which is a watery mixture containing fructose which provides energy for the sperm.

• Cowper’s or bulbourethral glands secrete mucus into the urethra during sexual arousal. This provides lubrication for intercourse and nelps neutralize the acidity of the urethra.

24


The Female Reproductive System

Anatomy:• The external female genitalia or vulva (page 166)

• the mons pubis, a fatty, rounded tissue area, covers the pubic symphysis. It becomes covered with hair during puberty.

• The labia majora are 2 elongated, pigmented, hair covered, fat padded skin folds which surround and enclose the labia minora.

25


• The Labia minora are 2 smaller, highly vascular, hair free folds.

• The clitoris is a small organ partly enclosed by the labia minora. It is composed of erectile tissue and is highly sensitive.

• The urethral opening lies between the clitoris and the vaginal opening.

26


Internal female reproductive organs (page 168)• 2 Ovaries are the primary reproductive organs.

They lie near the ends of the fallopian tubes (also called oviducts) in the upper pelvic cavity. They are held in place by several ligaments.

• The ovaries produce eggs called oocytes at regular intervals during the reproductive years. Eggs have 1/2 the number of chromosomes as the parent.

• They also produce the hormones estrogen and progesterone.

27


• The distal ends of the fallopian tubes are funnel shaped and have fingerlike projections called fimbriae. These create waves or currents which sweep the egg from the ovary into the pelvic cavity into the fallopian tube. They do not touch the ovary itself.

• The egg is propelled toward the uterus by the cilia on the walls of the fallopian tubes.

• If fertilization by a sperm occurs, it usually takes place in the upper third of the fallopian tube.

28


• The uterus is a pear shaped, muscular organ which is located between the bladder and the rectum. It will “incubate” the fertilized egg.– Its narrow, lower end is called the cervix. The

middle part of the uterus is called the body and the upper part is called the fundus.

• The vagina is a muscular tube that extends from the cervix to an opening on the exterior of the body.

29


– It serves as a birth canal and the female organ for sexual intercourse.

– It also permits the passage of menstral blood to the outside of the body.

• Note that in the pig, the urethra merges with the vagina. In humans, these openings are separate.

• Pigs (and most female mammals who bear young in litters) have uterine horns. This allows linear uterine distance for the young to develop.

30


The Breasts (page 167)

• are considered to be part of the reproductive organs

• are really modified sweat glands which produce milk to nourish newborn infants.

• milk production is stimulated by hormones only when birth has actually occurred.

• the nipple is at the center of each breast. It contains smooth muscles that can contract and cause the nipple to become erect.

31


• Surrounding the nipple is the pigmented areola. • Internally, the breasts contain mammary glands that

produce milk.– The glands consist of many milk producing

lobules. Contractile cells around each lobule allow the milk to be released and ducts deliver the milk to the nipple.

– Most of the breast consists of adipose tissue so breast size doesn’t indicate the potential for milk production.

32

Lab 12

REMINDER page 1of 2: Reproductive Systems

1. For the TOP activity on page 164, do not do number 1 and 2. Do number 3.

2. Do the bottom activity on page 164: The Male Reproductive System of the fetal pig. You are responsible for finding the following organs:

the testes, epididymis, and urethra3. In the female pig, you are responsible for finding

the ovaries, uterine horns, body of uterus and vagina.

33

REMINDER, page 2of 2: Reproductive Systems

4. You are responsible for these organs in both male and female pigs. Look at each other’s pigs to see an opposite sex pig.

5. For humans, use figure 17.3 as your guide for the male model and figures 18.3 and 18.4 for the female model. Find the comparable human organs as you located on the pigs.

6. There are suitcases on the table with models. Look at these.

Documents

1 The Urinary and Reproductive Systems Lab 12—7-11 Excretion refers to the processes that remove wastes and excess materials from the body. Urine is essentially