Regulation of Salt and Water Balance

These flashcards cover key concepts regarding the regulation of salt and water balance, including mechanisms of the kidneys, hormonal influences, and physiological responses related to fluid homeostasis.

Homeostasis

The maintenance of stable internal conditions in the body, particularly regarding water and salt balance.

Osmolality

A measure of the concentration of solutes in the blood, influencing water balance.

Baroreceptors

Sensory receptors located in the aortic arch and carotid sinus that detect changes in blood pressure.

Osmotic pressure

The pressure required to prevent the flow of water across a semipermeable membrane, critical in fluid balance.

Renin

An enzyme produced by the kidneys that initiates the renin-angiotensin system, affecting blood pressure and fluid balance.

Aldosterone

A hormone that promotes sodium and water reabsorption in the kidneys, raising blood volume.

Angiotensin II

A peptide hormone that causes blood vessels to constrict, increasing blood pressure and stimulating aldosterone release.

ADH (Vasopressin)

A hormone that increases water reabsorption in the kidneys, helping to regulate blood osmolality.

Nephrotic syndrome

A kidney disorder that causes the body to excrete too much protein in the urine, affecting fluid balance.

Baroreflex

A reflex mechanism by which the autonomic nervous system regulates blood pressure.

Sympathetic tone

The level of activity of the sympathetic nervous system, influencing heart rate and blood vessel constriction.

Oncotic pressure

The component of osmotic pressure exerted by proteins in blood plasma that influences fluid movement.

Extracellular fluid (ECF)

Fluid found outside of cells, including interstitial fluids and blood plasma.

Intracellular fluid (ICF)

Fluid found within cells, comprising a significant portion of total body water.

Hydrostatic pressure

The pressure exerted by a fluid due to gravity, important in fluid movement across capillary walls.

Atrial natriuretic peptide (ANP)

A hormone released by the heart that decreases reabsorption of sodium and water in the kidneys.

Vascular resistance

The resistance that must be overcome to push blood through the circulatory system, affecting blood pressure.

Juxtaglomerular apparatus

Structure in the kidney that detects changes in blood pressure and sodium concentration.

Volume overload

A condition in which there is an excess volume of fluid in the body, often detected by lung congestion.

Thirst mechanism

A physiological response triggered by osmoreceptors in the hypothalamus to increase fluid intake.

Fluid osmolarity

The concentration of solutes in a fluid, impacting the drive for water reabsorption.

Activation of sympathetic nervous system

A response to low blood pressure that increases heart rate and blood vessel constriction.

ACE (Angiotensin-Converting Enzyme)

An enzyme that converts angiotensin I to angiotensin II, crucial in blood pressure regulation.

Collecting ducts

Segments of the nephron in the kidney involved in concentrating urine and reabsorbing water.

Mediators of short-term blood pressure regulation

Primarily the autonomic nervous system, which responds rapidly to changes in blood pressure.

Water reabsorption

The process by which the kidneys reclaim water from urine, influenced by hormones like ADH.

Plasma volume contraction

A decrease in blood plasma volume, often leading to increased blood osmolality.

Efferent pathway

The pathway that carries signals away from the central nervous system, directing actions like heart rate increase.

Physiological stimuli

Environmental or internal changes that provoke a response in bodily functions or mechanisms.

Volume depletion

A condition characterized by a deficit in body fluid volume, often with decreased urine output.

G-protein coupled receptors

A large family of membrane receptors that mediate various physiological processes including hormone action.

Calcium and IP3 increase

Intracellular signaling processes involved in various functions such as vasoconstriction.

Principal cells

Cells in the renal collecting duct that are responsive to aldosterone and help regulate water and sodium balance.

Hyponatremia

A condition in which sodium levels in the blood are abnormally low, often caused by excessive water intake.

V1 and V2 receptors

Receptors in the collecting duct responsible for vasoconstriction and regulating water reabsorption, respectively.