Renal and Endocrine Systems: Function and Anatomy

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Questions and Answers

How does the structure of the glomerular basement membrane contribute to the formation of filtrate in Bowman's capsule?

The glomerular basement membrane has small pores that selectively allow water and small molecules like glucose to pass through, while retaining blood cells, platelets, and large molecules.

Describe how active transport in the proximal convoluted tubule (PCT) contributes to water reabsorption.

Active transport of sodium and other ions into the bloodstream from the PCT increases the water potential within the nephron. This causes water to leave the nephron via osmosis, reabsorbing the water into the body.

Explain how tubular secretion helps in maintaining blood pH balance, including examples of what is secreted into the tubules.

Tubular secretion helps regulate blood pH by secreting ions such as hydrogen ions and potassium ions into the tubules from the bloodstream, which helps to remove excess acids and maintain electrolyte balance.

If a urine analysis shows an elevated level of urea (3000mg/dl) compared to the normal value, what might this indicate about the body's metabolic processes or kidney function?

An elevated urea level could indicate increased protein breakdown, dehydration, or impaired kidney function, as the kidneys may not be efficiently removing urea from the blood. Signup and view all the answers

How do the kidneys contribute to maintaining electrolyte balance through the excretion of ions like sodium and potassium?

The kidneys regulate electrolyte balance by adjusting the reabsorption and secretion of ions such as sodium and potassium. This process helps maintain homeostasis and water retention, ensuring proper cellular function. Signup and view all the answers

Explain how a negative feedback mechanism regulates hormone levels in the body, providing a specific example related to either parathyroid hormone or blood sugar levels.

Negative feedback involves hormone levels triggering responses to counteract deviations from a set point. For example, if blood calcium levels drop, parathyroid hormone (PTH) is released. PTH increases blood calcium, and once normal levels are reached, PTH secretion decreases, preventing overshoot. Signup and view all the answers

Compare and contrast the effects of glucagon and insulin on blood glucose levels, including the specific cells in the pancreas responsible for producing each hormone.

Glucagon, produced by alpha cells in the pancreas, increases blood glucose levels by stimulating the breakdown of glycogen in the liver. Insulin, produced by beta cells, decreases blood glucose by promoting glucose uptake into cells and glycogen synthesis. Signup and view all the answers

Describe the role of follicle-stimulating hormone (FSH) in females, and explain how this relates to the production of a specific hormone by the ovary.

FSH stimulates the follicle cells in the ovary to produce large quantities of estrogen, which is essential for the development of female secondary sexual characteristics and the regulation of the menstrual cycle. Signup and view all the answers

A patient has their thyroid gland removed, but the parathyroid glands remain intact. Explain why this patient will still be able to maintain calcium homeostasis despite the thyroidectomy.

The parathyroid glands, which secrete parathyroid hormone (PTH), are responsible for regulating calcium levels. Since the parathyroid glands remain intact, they will continue to produce PTH, stimulating calcium release from bones, increasing calcium reabsorption in the kidneys, and promoting calcitriol production, thus maintaining calcium homeostasis. Signup and view all the answers

Differentiate between continuous and saltatory propagation of action potentials, highlighting the roles of myelination and axon structure in each type of propagation.

Continuous propagation occurs in unmyelinated axons, where the action potential moves step-by-step along the entire axon length, making it slower. Saltatory propagation occurs in myelinated axons, where the action potential jumps between Nodes of Ranvier, making it much faster due to reduced membrane capacitance and increased membrane resistance. Signup and view all the answers

Explain how the unique structure of the glomerulus, specifically the afferent and efferent arterioles, contributes to its function in ultrafiltration.

The wider afferent arteriole and narrower efferent arteriole create high blood pressure within the glomerulus. This elevated pressure forces blood plasma and small molecules out of the capillaries and into Bowman's capsule, facilitating ultrafiltration. Signup and view all the answers

Describe the roles of the descending and ascending limbs of the Loop of Henle in the reabsorption of water and ions, respectively.

The descending limb is permeable to water, allowing water to be reabsorbed into the surrounding interstitial fluid as it travels deeper into the medulla. Conversely, the ascending limb is impermeable to water but actively transports sodium and chloride ions out of the filtrate, contributing to the osmotic gradient in the medulla. Signup and view all the answers

A patient is diagnosed with a condition that impairs the function of the proximal convoluted tubule. Explain how this would affect urine composition.

Impairment of the proximal convoluted tubule would reduce the reabsorption of water, ions, and organic nutrients like glucose and amino acids. This would result in increased levels of these substances in the urine, leading to potential dehydration and nutrient loss. Signup and view all the answers

How does the collecting duct contribute to the regulation of blood osmolarity, and what hormone primarily influences this process?

The collecting duct reabsorbs water under the influence of antidiuretic hormone (ADH). ADH increases the permeability of the collecting duct to water, allowing more water to be reabsorbed into the bloodstream, thereby concentrating the urine and regulating blood osmolarity. Signup and view all the answers

Explain how the kidneys contribute to the stabilization of blood pH.

The kidneys regulate blood pH by reabsorbing or secreting hydrogen and bicarbonate ions in the distal convoluted tubule and collecting duct. They excrete hydrogen ions when the blood is too acidic and reabsorb bicarbonate ions. Conversely, excess bicarbonate is excreted when the blood is too alkaline. Signup and view all the answers

How do the kidneys help to regulate blood pressure, discussing at least two mechanisms by which they achieve this?

The kidneys regulate blood pressure through multiple mechanisms, including adjusting blood volume by controlling water reabsorption and secreting renin, which initiates the renin-angiotensin-aldosterone system (RAAS) to increase blood pressure. Signup and view all the answers

Describe two ways in which the kidney contributes to maintaining calcium homeostasis in the body?

The kidney contributes to calcium homeostasis by producing the active form of vitamin D, which enhances calcium absorption in the intestine, and by regulating calcium reabsorption in the renal tubules based on the body's needs. Signup and view all the answers

A patient is experiencing metabolic acidosis. How will the distal convoluted tubule respond to help restore blood pH balance?

In response to metabolic acidosis, the distal convoluted tubule will increase the secretion of hydrogen ions into the tubular fluid and increase the reabsorption of bicarbonate ions back into the bloodstream. This helps to remove acid from the blood and replenish the bicarbonate buffer. Signup and view all the answers

How does the depolarization of the presynaptic neuron lead to neurotransmitter release?

The action potential reaching the axon terminal causes depolarization, making the intracellular environment more positively charged, which opens voltage-gated calcium channels, triggering neurotransmitter release. Signup and view all the answers

Describe how a neurotransmitter's effect on the postsynaptic membrane is determined.

The effect of a neurotransmitter on the postsynaptic membrane depends on the characteristics of the receptors present on that membrane. Different receptors can trigger different responses, even for the same neurotransmitter. Signup and view all the answers

Outline the role of microglia cells after a stroke.

Following a stroke, microglia proliferate and remove dead neurons, cellular debris, and damaged tissue. They then deal with inflammation and initiate tissue repair within the affected brain area. Signup and view all the answers

Explain the function of the neurilemma and which cells form it.

The neurilemma is the outermost layer of the Schwann cell in the PNS that surrounds the nerve fiber. It is formed by Schwann cells and separates the layers of myelin. Signup and view all the answers

Summarize the events that lead to the repolarization of a neuron during an action potential.

After depolarization, sodium channels are inactivated, and voltage-gated potassium channels open. Potassium ions then move out of the cell, re-establishing a negative charge inside the cell and leading to repolarization. Signup and view all the answers

Compare and contrast the location and contents of the epidural space and the subdural space in relation to the meninges of the spinal cord.

The epidural space is located outside the dura mater and contains connective tissue and blood vessels. The subdural space is located between the dura mater and arachnoid mater and contains a thin film of fluid. Signup and view all the answers

Explain why damage to the vagus nerve is considered life-threatening, referencing its function and the organs it innervates.

Damage to the vagus nerve is life-threatening because it innervates many major organs, including the heart and digestive system, and plays a key role in parasympathetic control. Damage can disrupt essential functions such as heart rate and digestion, potentially leading to death. Signup and view all the answers

Describe the difference in function between the ventral and dorsal roots of a spinal nerve. What type of neuronal information does each transmit?

The ventral root contains axons of motor neurons, transmitting motor commands from the spinal cord to muscles and glands. The dorsal root contains axons of sensory neurons, transmitting sensory information from the body to the spinal cord. Signup and view all the answers

A patient presents with a painful rash along a specific dermatome. Based on the provided information, which structure is likely affected, and what is the condition commonly known as?

The dorsal root ganglia is likely affected, and the condition is commonly known as shingles. Signup and view all the answers

How do the functions of the oculomotor, trochlear, and abducens nerves collectively contribute to eye movement, and what type of muscle do they innervate?

The oculomotor, trochlear, and abducens nerves innervate the extrinsic muscles of the eye, controlling various aspects of eye movement. The oculomotor nerve controls most eye movements, the trochlear nerve controls superior oblique muscle, and the abducens nerve controls lateral rectus movement. Signup and view all the answers

How does the absence of centrioles in neurons affect their ability to regenerate after injury?

The absence of centrioles means neurons cannot divide, regenerate, or be replaced if lost to injury/disease. Signup and view all the answers

Explain how the structure of a synapse facilitates unidirectional communication between neurons.

The presynaptic neuron releases neurotransmitters that bind to receptors on the postsynaptic neuron. This one-way flow ensures the signal travels in a single direction. Signup and view all the answers

How do the differing lengths of preganglionic and postganglionic fibers reflect the functional differences between the sympathetic and parasympathetic nervous systems?

Sympathetic has short preganglionic and long postganglionic fibers, allowing widespread activation. Parasympathetic has long preganglionic and short postganglionic fibers, enabling localized control. Signup and view all the answers

Describe the functional relationship between sensory neurons, interneurons, and motor neurons in a reflex arc.

Sensory neurons carry information from receptors to interneurons in the CNS. Interneurons process the information and relay instructions to motor neurons, which then activate effectors. Signup and view all the answers

Outline the sequence of events at the axon terminal that lead to the release of neurotransmitters into the synaptic cleft.

Action potential arrives, Ca2+ enters the axon terminal, triggering exocytosis of neurotransmitters. Neurotransmitters diffuse across the synaptic cleft. Signup and view all the answers

What are the three zones of the adrenal cortex, and what class of hormones does each produce?

Zona glomerulosa produces mineralocorticoids. Zona fasciculata produces glucocorticoids. Zona reticularis produces gonadocorticoids. Signup and view all the answers

How does the structural arrangement of white and grey matter in the spinal cord contribute to its function in relaying sensory and motor information?

Grey matter contains neuron cell bodies for processing, while white matter, with its columns of nerve fibers, facilitates transmission of sensory and motor information between the brain and the periphery. Signup and view all the answers

Explain how the hypothalamus and pituitary gland work together to regulate hormone secretion.

The hypothalamus secretes releasing and inhibiting hormones that control the anterior pituitary. The posterior pituitary stores and releases hormones produced by the hypothalamus. Signup and view all the answers

Describe the role of the dorsal and ventral roots in transmitting sensory and motor information through the spinal cord.

Dorsal roots conduct sensory information into the spinal cord, while ventral roots carry motor commands out of the spinal cord. Signup and view all the answers

How does aldosterone affect sodium reabsorption in the kidneys, and what is the overall impact on blood volume and blood pressure?

Aldosterone increases sodium reabsorption in the renal tubules, leading to increased water retention, which increases blood volume and blood pressure. Signup and view all the answers

If a person has damage to their anterior pituitary, what are some potential hormonal deficiencies they might experience?

They might experience deficiencies in TSH, ACTH, FSH, LH, PRL, GH, and/or MSH. Signup and view all the answers

Explain how the peritubular capillaries contribute to the process of reabsorption in the nephron.

Peritubular capillaries surround the renal tubules and reabsorb water, ions, and nutrients from the filtrate back into the bloodstream. Signup and view all the answers

Describe the role of antidiuretic hormone (ADH) in regulating urine concentration, and indicate where it exerts its primary effect.

ADH increases the permeability of the collecting ducts to water, allowing more water to be reabsorbed into the bloodstream and concentrating the urine. Signup and view all the answers

What are the main structural differences between a somatic motor neuron and a visceral motor neuron, reflecting their functional differences?

Somatic motor neurons innervate skeletal muscles directly, while visceral motor neurons innervate cardiac muscle, smooth muscle, and glands through a two-neuron chain. Signup and view all the answers

Explain the roles of hydrostatic and osmotic pressure in glomerular filtration, and indicate which one drives the filtration process.

Hydrostatic pressure forces water and small solutes through the filtration membrane, while osmotic pressure opposes filtration by pulling water back into the capillaries. Hydrostatic pressure drives filtration. Signup and view all the answers

Flashcards

Nephron structure

Consists of renal corpuscle and renal tubule, including glomerulus and collecting duct.

Renal corpuscle

Composed of glomerulus, Bowman’s capsule, and filtration membrane; produces filtrate.