Practice Questions III (Urinary, Nervous, Cardiovascular & Blood Review)

Flashcards covering renal physiology, acid-base balance, neurobiology, and cardiovascular mechanics based on a comprehensive practice exam transcript.

Efferent arteriole

A blood vessel in the nephron with a smaller diameter than the afferent arteriole, resulting in an increase in the glomerular hydrostatic pressure.

Urine

A fluid composed of materials that are filtered and secreted (substances not reabsorbed in blood), typically maintaining a normal pH range of $4.5$ to $8.0$.

Glucose and Amino Acids

Organic solutes that are filtered into the nephron and normally completely reabsorbed in the PCT via active transport and protein co-carriers.

PCT (Proximal Convoluted Tubule)

The segment of the nephron most active at reabsorption of organic solutes, characterized by cuboidal cells with microvilli to increase surface area.

Descending limb of Loop of Henle

A segment of the nephron that is freely permeable to water, where the osmolarity of the filtrate gradually increases to a maximum of $1200\,mOsm$.

Ascending limb of Loop of Henle

A segment of the nephron with many transport proteins for $Na^{+}$ and $Cl^{-}$ reabsorption, where filtrate osmolarity decreases back to $300\,mOsm$ or less.

ADH (Antidiuretic hormone)

A hormone made by the hypothalamus that acts on the collecting ducts (and DCT) to increase the reabsorption of $H_{2}O$.

Aldosterone

A hormone that promotes the reabsorption of $Na^{+}$ in the DCT, causing the blood to reabsorb more water from the filtrate by osmosis.

Renin

An enzyme produced by the kidney that converts angiotensinogen into active angiotensin I to help raise blood pressure when it is too low.

Respiratory Acidosis

A condition characterized by a blood pH $< 7.35$ and a $pCO_{2}$ greater than $45\,mmHg$, often caused by impairment in ventilation.

Metabolic Acidosis

A condition indicated by a low blood pH with a low bicarbonate ($HCO_{3}^{-}$) level below $22\,mEq/L$, often caused by diabetes, starvation, or persistent diarrhea.

Myelin sheath

A lipid-rich layer surrounding axons; its destruction in diseases like Multiple Sclerosis slows nerve conduction speed dramatically.

Lidocaine

An anesthetic that blocks voltage-gated $Na^{+}$ channels, directly affecting the depolarization phase ($a$) and preventing action potentials from being triggered.

Reflex arc

The sequence of cell types through which an electrical signal passes: sensory neuron \rightarrow interneuron in the CNS \rightarrow motor neuron.

EPSP (Excitatory Postsynaptic Potential)

A graded potential caused by the opening of neurotransmitter-sensitive $Na^{+}$ channels, allowing $Na^{+}$ to move into the cell.

IPSP (Inhibitory Postsynaptic Potential)

A graded potential caused by the opening of neurotransmitter-sensitive $K^{+}$ channels (allowing ions to move out) or chloride channels.

Cerebellum

The part of the brain responsible for balance, posture, and coordination of movement.

Thalamus

The central mass of the diencephalon that functions as the major synapse or relay center for all ascending sensory impulses.

AB+ (Blood Type)

The universal blood receiver in packed blood transfusions because their erythrocytes have A, B, and Rh agglutinogens and no plasma antibodies.

O- (Blood Type)

The universal blood donor because their red blood cells have no agglutinogens (A, B, or Rh) on their surface.

Neutrophils

The most abundant white blood cells ($WBCs$) and the most abundant phagocytes in the blood.

Cardiac Output (CO)

The amount of blood moving into the aorta each minute.

QRS Wave

The electrical wave in an ECG that corresponds to the start of systole and causes the ventricles to contract.

Tunica media

The middle coat of an artery wall that contains the highest concentration of smooth muscle tissue.

Fascicle

A bundle of nerve cell axons wrapped together by a sheath of connective tissue called the perineurium.