URINARY QUIZ (EXAM #4 PART ONE)

What are the three functions of the urinary system?

Remove substances from blood (ex. N and S products), regulate various metabolic processes (ex. blood formation), and form urine

What six things do the kidneys regulate?

volume composition and pH of body fluids via urine formation, RBC formation via erythropoietin, blood pressure, absorption of Ca by activating vitamin D, elimination of N and S compounds (ex. urea, uric acid), formation and concentration of urine

What is a nephron?

Functional unit of kidney

What are the four nephron components?

Renal corpuscle, glomerulus, glomerular capsule, renal tubules

What is a glomerulus?

A tangle of blood arterioles

What is a glomerular capsule?

A sac that covers the glomerulus which together form the renal corpuscle, which filters waste and fluid from your blood to make urine

What is glomerulonephritis?

Inflammation of the glomerulus resulting from infection, malaria, diabetes, toxins, etc

What happens as a result of glomerulonephritis?

Glomeruli become plugged with antigen/anti-body complexes followed by WBC accumulation resulting in renal failure

What do protocytes do? (paper towel on strainer)

Provide an extra layer of filtration

What are renal tubules?

Micro-tubes in the kidneys that process filtered blood to reabsorb essential nutrients back into the bloodstream and convert the remaining waste into urine

Describe renal tube flow

Flows from glomerular capsule to proximal convoluted tubule to nephron loop to distal convoluted tubule to collecting duct

Overview: what are the three steps of urine formation?

Glomerular filtration, tubular reabsorption, tubular secretion

Describe glomerular flitration

The first step in urine formation, the movement of substances from glomerulus into glomerular capsule via pressure (filtration) and concentration gradient (diffusion), proteins and other large molecules do not pass and therefore increases colloid osmotic pressure pulling fluid back into glomerulus, diameter of afferent arterioles is larger than efferent arterioles and therefore increases pressure in afferent forces filtrate through glomerulus

What actions lead to acute renal failure?

Blood pressure drops (ex. from shock, hemorrhaging, dehydration), the afferent arteriole pressure decreases and therefore filtration rate decreases

Describe tubular reabsorption

The second step of urine formation, movement of substances from the tubular filtrate to the interstitial fluid to peritubular capillary via passive or active transport (ex. sodium and chloride ions, water, glucose)

Glucose requires ______ transport

active

If glucose molecules exceed capacity of active transport, glucose appears in urine, causing what?

Glucosuria as in diabetes mellitus

Glucosuria causes water to be drawn into the renal tubules, increasing urine volume and therefore causing what?

Osmotic diuresis

When does nephron syndrome occur?

Disease increases glomerular membrane permeability and allows proteins to pass into tubules and therefore urine (proteinuria), results in systemic edema

Describe tubular secretion

The third step in urine formation, movement of substances from the peritubular capillary to the interstitial fluid to the renal tubule (ex. H+, K+, ammonia, drugs, toxins)

What is the urine formation equation?

Urine volume = filtration volume + secretion volume - reabsorption volume

What are kidney stones?

Mineral deposits

What can kidney stones result in?

Renal inflammation, renal failure, or may plug lumen of ureter causing ureteritis and stopping flow of urine. May also plug urethral opening in bladder. 60% pass naturally but very painfully

Describe the composition of urine

Water 95%, Urea from amino acid catabolism, uric acid from nucleic acid catabolism, creatinine from creatine catabolism, electrolytes (water soluble), vitamins (water soluble),

What is the function or ureters?

To deliver urine from renal pelvis to urinary bladder

What are the three layers of the ureter?

Mucousal layer, muscular layer, fibrous coat

Describe the mucousal layer of the ureter

Mucous lining is transitional epithelium and extends into tubules

Infections of the urinary bladder (cystitis) easily ascend into the ureters and kidneys causing what?

Ureteritis and nephritis

UTI’s are more common for whom?

Women due to short urethra

Describe the muscular layer of the ureter

Peristalsis begins in pelvis and moves down ureters moving urine into bladder past valve

Kidney stones may plug lumen of ureter causing increased what?

Peristalsis

What is the function of the urinary bladder?

Storage of urine

What are the four layers of the urinary bladder?

Mucousal layer, submucosal layer, muscular layer, serous layer

Describe the mucosal layer of the urinary bladder

Transitional epithelium

Describe the submucosal layer of the urinary bladder

Connective tissue with increasing number of elastic fibers

Describe the muscular layer of the urinary bladder

Interlaced smooth muscle forms the detrusor muscle and internal urethral sphincter

Describe the serous layer of the urinary bladder

Parietal peritoneum (superior surface only)

What is the function of the urethra?

Convey urine from bladder to expulsion (and carry semen in males)

What are the two layers of the urethra?

Mucosal layer and muscular layer

Describe the muscular layer of the urethra

Smooth muscle, important in ejaculation

Describe micturition

Bladder stretch receptors cause urination reflex and therefore contraction of detrusor and relaxation of internal sphincter

Urine flow is restricted by contraction of what?

External urethral sphincter (skeletal muscle)

Young children may lack unconscious control of the external sphincter resulting in what? Most common in ADD/ADHD children

Enuresis, common at night = nocturnal enuresis

What is incontinence?

Loss of micturition control, caused by spinal cord damage, pregnancy, obesity, age or pathology ex. enlarged prostate

What is stress urinary incontinence (SUI)?

Inability of the urethra/sphincter to properly regulate outflow of urine from bladder due to stretching (stress) of the pelvic floor muscles and stretching of the connective tissue between the bladder and vagina during pregnancy

As you get older, your number of kidney cells _____

decreases

As you get older, your number of glomeruli _____

decreases

As you get older, fat deposits in tubules ______

increase, which decreases absorption

As you get older, renal blood flow _____

decreases

As you get older, bladder loses elasticity and therefore the volume ______

decreases

As you get older, the urge to urinate is _____

delayed

What is the function of the male reproductive system?

Production and discharge of sperm, copulation

What is the function of testes?

Production of sperm cells and testosterone

What is the function of seminiferous tubules?

Site of production of sperm cells from puberty until death

What is the function of sperm cells?

Carry male chromosomes

What are the two components of testes?

Seminiferous tubules and sperm cells

What are the three parts of sperm?

Head: nucleus with chromosomes (23)

Midpiece: mitochondria

Tail/flagellum

Germ cells give rise to what?

Gametes

Epithelial cells of the seminiferous tubules give rise to what?

Testicular cancer in young men

What if the function of the epididymis?

Nutrition and maturation of sperm

How long can sperm live once they are mature?

2-3 weeks

What is the function of the vas (ductus) deferens?

Transport sperm to ejaculatory duct

The vas deferens are surgically obstructed during a vasectomy to prevent what?

Sperm release; knots, thermal scarring or clips are the most commonly used

True or false a reversal of a vasectomy is a high success procedure

False, low success

What are the three function of the seminal gland (vessicle)?

1. Secrete alkaline fluid to moderate pH of ejaculatory duct and acid from epididymis

2. Produce fructose for energy for sperm

3. Produce prostaglandins to stimulate muscular contractions in female reproductive tract to help move sperm

All 3 are released at emission

What are two functions of the prostate gland?

1. Secrete alkaline fluid to moderate pH of acid from epididymis and in vagina

2. Activate sperm

When is prostatic fluid released?

At emission when it joins sperm from the vas deferens and seminal fluid

What is prostate hyperplasia?

Enlargement of the prostate due to aging or cancer

What is the function of the bulbourethral glands?

Produce mucus for lubrication and alkaline fluid, commonly released during arousal

Semen is the ejaculate that contains what four elements?

Sperm (200-600 million), seminal fluid, prostatic fluid, bulbourethral fluid

How long can sperm live in women?

Up to 48 hours

What does the ejaculate contain for those with a vasectomy?

Seminal fluid, prostatic fluid, bulbourethral fluid

Why do men have so much sperm?

To plug up the cervix to stop other male sperm or to have killer sperm that fights the plug

What is the function of the scrotum?

Enclose testes and moderate their temp (3C/5F) below body temp via movements of smooth muscle

What are the three functions of the penis?

Convey urine, convey semen, copulatory organ

What are the five components of the penis and their functions?

Corpus cavernosum: erectile tissue

Corpus spongiosum: erectile tissue

Penile urethra: carry urine and semen

Glans penis: stimulation

Prepuce (foreskin): stimulation

What is circumcision?

Surgical removal of the prepuce

Describe the process of an erection (how much blood goes into penis)

Physical or psychological stimulation, nitric oxide is released, erectile chemicals are produced, penile arteries dilate, penile veins constricted by pressure, erection

What is impotency?

Failure to obtain/maintain an erection

What might temporary impotency result from?

Alcohol, drugs, psychological factors (performance anxiety)

What might permanent impotency result from?

Vascular or nerve disorders

What do Viagra and Cialis do?

Prevent an enzyme from breaking down an erectile chemical necessary for maintaining an erection, therefore sustaining the erection (arousal is still required)

What is an orgasm?

Culmination of stimulation resulting in emission

What is emission?

Release of sperm, seminal, bulbourethral and prostatic fluid into the urethra (membranous and penile) to form semen

The fluid expelled from the penis during arousal is mostly what?

Bulbourethral fluid, but some sperm may exit before full ejaculation

What is ejaculation?

Rhythmic contractions of smooth muscle at base of erectile columns therefore increasing pressure forcing semen from penile urethra

What happens immediately after ejaculation?

Penile arteries constrict while penile veins dilate resulting in flaccid penis

Describe the refractory period

In males subsequent erections are not possible for over 20 minutes

Following ejaculation the urge to urinate removes what?

Residual semen (and fructose) from the urethra, decreasing chance of infection

Emission may occur without ejaculation resulting in what?

Temporary pain in the reproductive tract, results from loss of psychological stimulation

What are nocturnal emissions or wet dreams?

Unconscious emission and ejaculation which occur in adolescent males due to increasing hormone levels

Describe the first step of endocrine control of male reproduction

Hypothalamus secretes gonadotropin-releasing hormone (GnRH)

Describe the second step of endocrine control of male reproduction

Anterior pituitary: GnRH stimulates release of the gonadotropins called Interstitial Cell Stimulating Hormone (ISCH) and follicle-stimulating hormone (FSH)

Describe the third step of endocrine control of male reproduction

Testes/seminiferous tubule (interstitial cells):

1. Stimulated by ICSH to produce testosterone

2. Stimulated by FSH and testosterone to begin spermatogenesis

3. As sperm counts increase, secretion of inhibin by testes inhibit: hypothalamus from secreting GnRH, ant. pit. from secreting gonadotropins

Increased levels of testosterone will inhibit what?

Hypothalamus and ant. pit. from secreting

What are the four actions of testosterone?

Masculinization of embryo at 7 weeks, descent of testes en utero, enlargement of testes at puberty, secondary sex characteristics

What are some male secondary sex characteristics?

Increased body hair

Increased thyroid cartilage (adam’s apple)

Deeper voice

Thicker skin

Increased muscle mass

Wider shoulders

Thicker bones

Increased hematocrit

Increased libido

As males age, testosterone levels _____

decrease

What is the function of the ovary?

Production of gametes (eggs)/hormones (homologous to testes)

What are follicles? (Egg carton)

Cavities within ovary containing oocytes