Functions and Structures of the Kidneys and Reproductive System

Flashcards covering key concepts related to kidney functions, blood filtration processes, and reproductive system physiology.

functions of the kidneys

Regulation of ECF volume/blood pressure, regulation of osmolarity, maintenance of ion balance, homeostatic pH regulation, excretion of wastes, and production of hormones.

functional unit of the kidney

The nephron.

path of urine

Kidney -> Ureter -> Urinary Bladder -> Urethra.

outer cortex and inner medulla

two main regions of the kidney

salt concentration differ in the outer cortex and inner medulla

Salt concentration increases as you move from the cortex to the medulla.

The glomerular capsule (or Bowman's capsule)

nephron surrounds the glomerulus to filter blood

The nephron loop (or Loop of Henle)

Fluid flows from the proximal tubule into this structure

collecting duct

The distal tubules of several nephrons drain into this and then flows into the ureter

Trace the path of blood flow through the kidney, starting from the renal artery.

Renal artery -> Afferent arterioles -> Glomerulus -> Efferent arterioles -> Peritubular capillaries -> Venules and renal vein.

hydrostatic pressure high in the glomerulus

To facilitate the filtration of fluid from the blood into the nephron.

Why is hydrostatic pressure low in the peritubular capillaries?

To allow for the rapid reabsorption of fluid back into the blood.

kidney 'Filtration'.

The filtering of body fluids from the blood in the glomerulus into the lumen of the nephron.

Kidney Reabsorption

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

kidney 'Secretion'.

The process of adding nonessential solutes and wastes from the body fluids into the filtrate.

kidney 'Excretion'.

The process of releasing the processed filtrate (urine) from the body.

Approximately how much fluid is filtered into the glomerular capsule per day?

About 180 L/day is filtered.

Approximately how much urine is excreted per day?

About 1.5 L/day of urine is excreted.

During glomerular filtration, what components are typically filtered?

Water, nitrogenous waste, nutrients, salts.

During glomerular filtration, what components are not filtered?

Blood cells, albumins, platelets.

Glomerular Filtration Rate (GFR)

The volume of fluid filtered from the glomeruli into Bowman's space per unit time.

increased resistance in the afferent arteriole

It decreases GFR.

increased resistance in the efferent arteriole

It increases GFR.

tubuloglomerular feedback

A local control pathway where fluid flow through the nephron loop influences GFR by signaling the afferent and efferent arterioles.

The macula densa cells

cells that sense tubule flow in tubuloglomerular feedback

primary function of the proximal convoluted tubule (PCT)

Isosmotic reabsorption of the majority of solutes and water from the filtrate.

two cellular specializations that aid in reabsorption in the proximal tubule

Microvilli (brush border) to increase surface area and a high density of mitochondria for active transport.

Tubular secretion

key process in the PCT

Difference of permeability in the nephron loop in ascending vs descending limb

The descending limb is permeable to water only, while the ascending limb is permeable to salts only.

Main function of the nephron loop

To create a dilute filtrate and establish a salt gradient in the medulla.

countercurrent multiplier

the process by which the nephron loop establishes the medullary salt gradient

Where does hormone-sensitive regulation of ions and water balance occur in the nephron?

The distal tubule and collecting duct.

What hormone increases Ca2+ reabsorption in the distal tubule?

Parathyroid hormone (PTH).

To make the blood more basic, what happens to protons and bicarbonate in the distal tubule?

Protons will be secreted and bicarbonate will be reabsorbed.

What is the formula for calculating the amount of a substance excreted in urine?

Excretion = Filtration + Secretion - Reabsorption.

Micturition is a spinal reflex; which nervous system branch causes bladder contraction?

The parasympathetic nervous system.

During bladder filling, is the external sphincter contracted or relaxed?

It is tonically contracted.

What are the three functional fluid compartments in the body?

Intracellular fluid (ICF), plasma, and interstitial fluid.

What two fluids compose extracellular fluid (ECF)?

Plasma and interstitial fluid.

What hormone, also known as ADH, stimulates water reabsorption in the kidney?

Vasopressin.

What are the two primary stimuli for vasopressin release?

Low blood volume and high osmolarity.

How does vasopressin make the collecting duct permeable to water?

It stimulates the insertion of aquaporin water channels into the cell membrane.

What is the primary action of the hormone aldosterone?

It increases Na+ reabsorption and K+ secretion in the renal collecting duct.

Aldosterone is part of what hormonal system that regulates blood pressure?

The renin-angiotensin system (RAS).

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

Renin.

What enzyme converts angiotensin I to active angiotensin II?

Angiotensin converting enzyme (ACE).

List three effects of angiotensin II that lead to an increase in blood pressure.

Stimulates aldosterone release, increases vasopressin secretion, stimulates thirst, and causes widespread vasoconstriction.

What is the function of natriuretic peptides (ANP and BNP)?

They promote Na+ and water excretion, which decreases blood pressure.

What stimulates the release of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)?

Increased stretch in the myocardial cells due to increased blood volume.

What is the normal pH range of human blood?

7.35 to 7.45.

Name the three primary mechanisms that regulate acid-base balance in the body.

Chemical buffer systems, the lungs (eliminating CO2), and the kidneys (eliminating H+ and reabsorbing HCO3-).

How does the respiratory system compensate for blood that is too acidic?

Respiration rate increases to exhale more CO2.

How do the kidneys respond during a state of acidosis?

They excrete additional hydrogen ions (H+) and retain additional bicarbonate (HCO3-).

What is the difference between respiratory acidosis and metabolic acidosis?

Respiratory acidosis is caused by retention of CO2 due to lung problems; metabolic acidosis is caused by increased acid production or loss of bicarbonate.

What acid-base imbalance develops from hyperventilation?

Respiratory alkalosis.

What is the appropriate renal compensation for respiratory alkalosis?

The kidneys would decrease proton excretion and decrease bicarbonate reabsorption.

What is the process of producing sperm and egg cells called?

Gametogenesis.

What cells differentiate into primary spermatocytes in spermatogenesis?

Spermatogonial cells.

In oogenesis, where are primary oocytes arrested at birth?

Prophase of Meiosis I.

What phase is the secondary oocyte arrested in until fertilization?

Metaphase II.

Which gene on the Y chromosome directs testes development?

The SRY gene.

What two hormones are produced from the testes due to the SRY gene?

Testosterone and Anti-Müllerian hormone (AMH).

What does Anti-Müllerian hormone (AMH) cause during development?

Regression of the Müllerian ducts.

What role does testosterone play during embryonic development?

It promotes development of male internal and external genitalia.

What hormone from the anterior pituitary causes ovarian follicle development?

Follicle-stimulating hormone (FSH).

What hormone surge triggers ovulation?

Luteinizing hormone (LH).

What two hormones are produced by the corpus luteum during the luteal phase?

Estrogen and progesterone.

What is the primary role of progesterone during the menstrual cycle?

To prepare and maintain the uterine lining for implantation.

The phase of the menstrual cycle where the uterine lining grows due to estrogen is called the _.

proliferative phase.

The menstrual phase occurs when levels of which two hormones are low?

Estrogen and progesterone.

How do hormonal birth control pills prevent pregnancy?

By providing exogenous hormones that suppress the LH surge.

What two hormones does GnRH stimulate from the anterior pituitary in males?

Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH).

What does LH stimulate in males?

It stimulates interstitial cells (Leydig cells) to secrete testosterone.

In males, what does FSH stimulate nurse cells to secrete?

Androgen-binding protein (ABP).

Which branch of the autonomic nervous system promotes the erection reflex?

The parasympathetic nervous system.

What signaling molecule causes vasodilation in penile arterioles?

Nitric oxide (NO).

Which branch of the autonomic nervous system promotes the ejaculation reflex?

The sympathetic nervous system.

What is the source of the fructose that nourishes sperm in semen?

The seminal vesicles.