A&P Exam IV

Can you live with just one kidney?

Yes

How do kidneys regulate blood pH?

By excreting hydrogen ions and conserving bicarbonate ions.

How does aldosterone affect sodium and potassium levels?

Aldosterone increases sodium reabsorption and potassium excretion.

How does the structure of the loop of Henle facilitate urine concentration?

The countercurrent arrangement allows for efficient solute reabsorption and concentration gradient maintenance.

What are nephrons?

The functional units of the kidneys

What are the main components of the urinary system?

2 kidneys

What are the primary functions of the kidneys?

Excretion of wastes

What are the three layers of tissue surrounding each kidney?

Renal capsule

What are the three main sections of the renal tubule?

Proximal convoluted tubule (PCT)

What are the three processes involved in the formation of urine?

Simple filtration

What are the two distinct regions of the kidneys?

Renal cortex (superficial) and renal medulla (deep).

What are the two types of cells found in the collecting duct?

Principal cells and Intercalated cells

What can cause urine to appear cloudy?

Possible indication of infection

What color is healthy urine?

Pale yellow to amber.

What do Intercalated cells do?

Maintain the body's acid-base balance by secreting hydrogen ions (H+) or bicarbonate ions (HCO3-)

What do macula densa cells respond to?

They respond to high Na+ levels in the filtrate.

What does renin convert angiotensinogen into?

Angiotensin I

What effect does aldosterone have on the kidneys?

Increases reabsorption of Na+ and water

What enzyme do kidneys secrete to help regulate blood pressure?

Renin.

What enzyme is secreted by juxtaglomerular cells in response to low blood pressure?

Renin

What happens during the voiding reflex?

Detrusor muscles contract

What happens to glucose excretion when plasma concentration reaches the renal threshold?

Glucose excretion becomes zero until the renal threshold is reached.

What happens to urine production when it's cold?

People tend to pee more due to increased blood pressure and reduced blood flow to the kidneys.

What initiates the renin-angiotensin-aldosterone (RAA) pathway?

Dehydration

What initiates the voiding reflex?

Stretch of the bladder

What is angiotensin II's role in the body?

Stimulates aldosterone secretion

What is cold-induced diuresis?

Increased urination due to blood vessel constriction in cold weather

What is countercurrent multiplication in the loop of Henle?

It is a system where the descending loop is permeable to water and the ascending loop is permeable to solutes

What is micturition?

The discharge of urine from the urinary bladder

What is the composition of filtrate compared to plasma?

Filtrate is similar to plasma but lacks plasma proteins.

What is the effect of high osmolarity in the medullary interstitium?

It drives water reabsorption and helps concentrate urine.

What is the equation for the excretion rate of a substance S?

Excretion rate of S = filtration rate of S − reabsorption rate of S + secretion rate of S.

What is the equation for the excretion rate of a substance?

Excretion rate = filtration rate - reabsorption rate + secretion rate.

What is the fate of nitrogenous waste products like urea in the kidneys?

They are reabsorbed only to a slight extent.

What is the fluid entering the glomerulus called?

Filtrate.

What is the function of intercalated cells?

To regulate blood pH by secreting hydrogen ions and reabsorbing bicarbonate.

What is the function of principal cells?

To respond to antidiuretic hormone (ADH) and aldosterone.

What is the function of the external urethral sphincter?

Skeletal muscle that contracts to prevent urine release

What is the function of the internal urethral sphincter?

Smooth muscle that contracts to prevent urine release

What is the function of the juxtaglomerular apparatus (JGA)?

It regulates GFR and includes afferent and efferent arterioles

What is the function of the ureters?

To convey urine from the kidneys to the urinary bladder.

What is the glomerular filtration rate (GFR) in a healthy adult?

About 115-125 ml/min

What is the guarding reflex?

A mechanism that prevents involuntary release of urine during bladder filling

What is the juxtaglomerular apparatus (JGA)?

A structure that regulates blood pressure in the kidneys

What is the last stop in urine formation?

The collecting duct

What is the main job of the kidneys?

To regulate blood volume and composition

What is the myogenic response in GFR autoregulation?

It is the intrinsic ability of smooth muscle to respond to changes in arterial pressure.

What is the net filtration pressure in the glomerulus?

10 mmHg (calculated as 55 mmHg - (30 mmHg + 15 mmHg)).

What is the normal composition of urine?

95-98% water and 2-5% solutes

What is the normal pH range of urine?

Approximately 4.5 to 8

What is the permeability of the collecting duct to water?

Selectively permeable to water

impermeable to solutes (NaCl)

What is the primary focus of nephrology?

The study of the kidneys.

What is the primary function of Principal cells?

Involved in sodium (Na+) and water reabsorption

What is the primary function of the kidneys?

To maintain fluid and electrolyte balance and regulate blood pH.

What is the process of glomerular filtration?

The first step in urine formation where blood is filtered in the glomerulus.

What is the purpose of reabsorption in the nephron?

To alter the composition and volume of glomerular filtrate during its passage through the nephron.

What is the relationship between blood volume and urine output?

Urine output fluctuates based on blood volume and hydration status.

What is the renal corpuscle made of?

The glomerulus and the glomerular (Bowman's) capsule.

What is the role of glomerular capillaries in filtration?

They are fenestrated

What is the role of parathyroid hormone and calcitonin in the kidneys?

They regulate the reabsorption of calcium and phosphate.

What is the role of the macula densa?

To monitor sodium concentration and regulate blood pressure.

What is the significance of high medullary interstitial osmolarity?

It creates a concentration gradient for water reabsorption

What is the significance of inulin in measuring GFR?

Inulin is filtered only and is neither reabsorbed nor secreted

What is the transport maximum (Tm) in relation to glucose?

It is the maximum capacity for reabsorption of glucose

What is tubular reabsorption?

The process of reclaiming water and solutes from the filtrate back into the blood.

What is tubular secretion?

The process of transferring substances from the blood into the filtrate.

What muscles line the wall of the urinary bladder?

Detrusor muscles

What percentage of filtered sodium is reabsorbed in the proximal tubule?

65%.

What regulates water permeability in the collecting duct?

The number of membrane-inserted aquaporins

What role does antidiuretic hormone (ADH) play in water reabsorption?

ADH increases the permeability of the distal convoluted tubules and collecting tubules

What substances are cleared from the blood by secretion into the convoluted tubules?

Hydrogen ions (H+)

What substances are reabsorbed by active transport in the nephron?

Amino acids

What types of cells are found in the distal convoluted tubule?

Principal cells and intercalated cells.

What waste products do the kidneys excrete?

Urea

Which body systems work closely with the urinary system?

The circulatory system and endocrine system.

What is the primary function of the male reproductive system?

To produce sperm and deliver it to the female.

What are the primary sex organs in males?

Testes.

At what stage of life does the male reproductive system become active?

Puberty.

What are gametes?

Specialized cells for sexual reproduction

sperm in males and ova (eggs) in females.

What is formed when sperm and egg fuse?

A zygote, which is the first cell of a new individual.

What are the accessory reproductive organs in males?

Ducts, glands, and external genitalia.

What does the hypothalamic-pituitary-gonadal (HPG) axis regulate?

The production of gametes and sex hormones.

What hormones are involved in the HPG axis?

GnRH, FSH, LH, testosterone, and inhibin.

What is the role of androgens in the male reproductive system?

They are responsible for the development and function of reproductive organs and secondary sexual characteristics.

What is meiosis?

A unique kind of nuclear division that reduces the number of chromosomes in gametes by half.

What are the two primitive duct systems in embryos?

Wolffian ducts (develop into male) and Müllerian ducts (develop into female).

What is the SRY gene responsible for?

It directs male development by initiating the production of testis-determining factors.

What is cryptorchidism?

A condition where the testes do not descend into the scrotum, affecting about 3% of male births.

What are the two tunics surrounding each testis?

Tunica vaginalis and tunica albuginea.

What is the function of interstitial (Leydig) cells?

They produce testosterone.

What is the function of Sertoli (sustentacular) cells?

They protect germ cells and promote their development.

What is the purpose of the scrotum?

To keep the testes 3°C lower than core body temperature for optimal sperm production.

What muscles help maintain the temperature of the scrotum?

Dartos (smooth muscle) and cremaster (skeletal muscle).

What is spermatogenesis?

The process of sperm production.

What is the significance of the zygote?

It is the first cell of a new individual, from which all body cells arise.

What are secondary sexual characteristics influenced by sex hormones?

Features such as pubic and axillary hair, associated scent glands, and voice pitch.

What is the earliest time reproduction is possible?

During puberty, when reproductive organs grow to adult size and become functional.

What is the genetic sex determination in humans?

XX for female and XY for male.