Paramedicine Medical Physiology I Lecture 16

G-protein coupled receptors (GPCRs) are activated when a ligand binds, triggering a conformational change. This activates associated G proteins, leading to downstream signaling.

G proteins have a trimeric structure: alpha, beta, and gamma subunits. The alpha subunit binds GTP/GDP, determining activity.

G protein activation occurs when GDP is replaced by GTP, causing the alpha subunit to detach from the beta/gamma complex.

A small molecule that relays signals from a receptor to intracellular targets, changing cellular activity based on the first messenger.

A signaling pathway where cAMP, a second messenger, activates protein kinase A (PKA), leading to cellular responses.

An extracellular signal molecule, like a hormone or neurotransmitter, that initiates a cellular response.

Second messenger systems amplify cell signaling by creating cascades of reactions, making cellular effects more significant in response to a smaller extracellular signal.

Second messengers relay signals from receptors to intracellular targets to initiate cellular responses. For example, cAMP signals that causes cellular changes in response to a hormone.

The part of the nephron responsible for fine-tuning urine composition, with a focus on secretion rather than reabsorption. It's lined by cuboidal cells with minimal microvilli, and is located in the renal cortex.

Different parts of the nephron have distinct directions of fluid flow (both tubular fluid and interstitial fluid) and specialized functions for reabsorbing water and solutes. This helps regulate urine concentration and composition.

A large tube in the kidney that gathers fluid from multiple nephrons. It's found in both the cortex and medulla and is lined with cells that control water and electrolyte reabsorption.

The collecting duct is lined by two main types of cells: intercalated cells and principal cells. They play key roles in regulating acid-base balance and electrolyte concentrations in the final urine.

The final conduit in the collecting system, it receives fluid from the collecting ducts and delivers it to the minor calyx, leading to the final urine output.

The process where the kidneys remove waste products, excess fluids, and electrolytes from the blood, creating a filtrate that will become urine.

The fluid produced by the kidneys during filtration, containing water, waste products, nutrients, and electrolytes, but not blood cells or large proteins.

The process where the kidneys reabsorb valuable nutrients, water, and electrolytes back into the bloodstream from the filtrate.

The process where the kidneys actively transport waste products and excess substances from the blood into the filtrate, making the urine more concentrated.

This hormone helps regulate sodium and potassium balance in the body by stimulating pumps in the DCT to reabsorb sodium and excrete potassium.

The kidneys secrete hydrogen ions into the filtrate, removing excess acid from the body and helping maintain a balanced pH.

These proteins transport toxins and drugs from the body into the filtrate for excretion.

The complex process in which the kidneys filter blood, reabsorb necessary substances, and secrete waste to produce urine, which is then excreted.

The kidneys play a vital role in maintaining the body's fluid, electrolyte, and acid-base balance, filtering waste and producing urine.

Smooth muscle contraction can be triggered by various mechanisms, including mechanical stress, neurotransmitter (NT) binding to ligand-gated calcium channels, and NT or hormone binding to G protein-coupled receptors (GPCR).

Channels that open in response to physical stretching of the muscle cell, allowing calcium ions to enter and initiate contraction.

Neurotransmitters (NTs) can directly bind to and open calcium channels, triggering muscle contraction.

Neurotransmitters or hormones bind to G protein-coupled receptors, initiating a cascade of intracellular events leading to muscle contraction.

Membrane receptors that, upon ligand binding, initiate a signaling cascade within the cell.

A series of biochemical events triggered by GPCR activation. This pathway amplifies and transmits signals inside the cell, ultimately leading to the desired outcome, such as muscle contraction.

GPCR activation provides numerous variations in regulating cellular activities. This control over cellular functions is a key aspect of cell signaling and response.

The legal right granted to the creator of a work to copy, distribute, and display the work in various mediums.

Legal statement regarding the protection of materials created. Ensures respect for copyright.

Rules and regulations set by a college on student behavior and usage of materials.

Long, thin-walled blood vessels that run parallel to the loops of Henle in juxtamedullary nephrons. They arise from efferent arterioles and are important for forming concentrated urine.

A specialized structure in each nephron, located where the distal tubule of the nephron loop contacts the afferent arteriole (and sometimes the efferent arteriole). It plays a crucial role in regulating blood pressure and filtrate formation rate.

Tall, closely packed cells located in the ascending limb of the nephron loop. They act as chemoreceptors, sensing the NaCl concentration in the filtrate.

An enzyme produced and secreted by granular cells in the JGC. It plays a crucial role in regulating blood pressure by activating the renin-angiotensin-aldosterone system (RAAS).

Specialized cells located between the arteriole and tubule cells in the JGC. They are interconnected via gap junctions and may facilitate communication between macula densa and granular cells.

Macula densa cells act as chemoreceptors, sensing the sodium chloride (NaCl) concentration in the filtrate flowing through the ascending limb of the nephron loop.

Granular cells act as mechanoreceptors, detecting blood pressure changes in the afferent arteriole. They also contain secretory granules that release renin, an enzyme involved in regulating blood pressure.

The JGC plays a crucial role in regulating the rate of filtrate formation and blood pressure by coordinating the activity of the macula densa, granular cells, and mesangial cells.

The JGC is essential for maintaining proper blood pressure and fluid balance in the body by regulating the release of renin and adjusting the rate of filtrate formation.

A cup-shaped structure surrounding the glomerulus, responsible for initial filtration of blood in the nephron.

The outer layer of the glomerular capsule, formed by simple squamous epithelium.

The inner layer of the glomerular capsule, made up of branching epithelial cells called podocytes.

Specialized epithelial cells in the visceral layer of the glomerular capsule, with extensions called foot processes that form filtration slits.

Gaps between the foot processes of podocytes, allowing filtrate to pass into the capsular space.

The first part of the nephron after the glomerular capsule, responsible for reabsorbing most of the nutrients and water from the filtrate.

A U-shaped structure in the nephron, crucial for concentrating urine, with a descending limb and an ascending limb.

The part of the nephron loop that travels down into the medulla, allowing water reabsorption.

The part of the nephron loop that travels up towards the cortex, reabsorbing ions.

Different drugs can target specific segments of the nephron to achieve specific effects on the body's fluid and electrolyte balance.

Specialized capillaries in the nephron responsible for filtering blood. They are unique because they are fed and drained by arterioles, with the afferent arteriole entering and the efferent arteriole leaving.

Low-pressure, porous capillaries that surround the renal tubules. They are adapted for absorption of water and solutes from the filtrate back into the bloodstream.

The arteriole that brings blood into the glomerulus. It has a larger diameter than the efferent arteriole, contributing to the high blood pressure in the glomerulus.

The arteriole that carries blood away from the glomerulus. It has a smaller diameter than the afferent arteriole, helping maintain high pressure in the glomerulus for efficient filtration.

The high blood pressure in the glomerulus is due to a combination of factors:

1. The afferent arteriole is larger than the efferent arteriole, creating a pressure difference.
2. Arterioles are naturally high-resistance vessels, further contributing to the pressure.

Cells located in the afferent arteriole that are responsible for producing and releasing renin, a key enzyme in regulating blood pressure.

Tall, closely packed cells located in the ascending limb of the nephron loop. They act as chemoreceptors, sensing the NaCl concentration in the filtrate.

A signaling pathway where a first messenger (hormone/neurotransmitter) triggers the production of a second messenger (cAMP, etc.) to relay signals.

Second messengers amplify signals, allowing small initial stimuli to create large cellular effects.

A hormone or neurotransmitter that triggers a cascade of events in a cell by activating a receptor.

Second messenger systems allow for signal amplification and efficient control of complex cellular processes.