Action Potential in Muscle Cells

What is the main function of the endoplasmic reticulum (ER)?

To make lipids and proteins for the cell's membranes and proteins for secretion (correct)
To break down organic molecules
To carry substances from one organelle to another
To store calcium ions

What is the main function of lysosomes?

To release glucose from glycogen
To carry substances from one organelle to another
To make phospholipids
To break down particles like cellular debris and waste (correct)

What is the main component of peroxisomes?

Hydrolytic enzymes
Ribosomes that make polypeptides
Vesicles that carry substances from one organelle to another
Enzymes that break down organic molecules (correct)

What is the function of the smooth endoplasmic reticulum (SER) in liver cells?

To release glucose from glycogen (A) Signup and view all the answers

What is the main difference between the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER)?

The RER has ribosomes attached to it, while the SER does not (A) Signup and view all the answers

What is the pH of the interior of lysosomes compared to the rest of the cytoplasm?

More acidic (near pH 5) (A) Signup and view all the answers

What happens at the end of the refractory period?

The potassium channels close and the resting period is reestablished (D) Signup and view all the answers

What is the main difference between action potentials in muscle cells and neurons?

Muscle cells require a stronger depolarization to reach the threshold (B) Signup and view all the answers

What happens when the membrane potential increases enough to reach the threshold?

The voltage-gated sodium channels and sarcolemma open (A) Signup and view all the answers

What is the main difference between the action potential in muscle cells and heart cells?

Muscle cells are triggered by a transmitter, while heart cells are triggered by electrochemical stimulation (D) Signup and view all the answers

What is the role of chloride channels in muscle cell action potentials?

They open to stabilize the membrane potential (D) Signup and view all the answers

Why is the refractory period short in muscle cells?

To allow for quick muscle contractions (B) Signup and view all the answers

What serves as the cardiac pacemaker in the heart?

Sinoatrial node (D) Signup and view all the answers

Where is the atrioventricular (AV) node located?

In the middle of the heart (A) Signup and view all the answers

Which electrolyte moves out of the cell during cardiac muscle contraction?

Sodium (A) Signup and view all the answers

What is the main role of Purkinje's fibers in the heart?

To transmit electrical impulses through the heart (A) Signup and view all the answers

Which structure separates the left and right ventricles in the heart?

Interventricular septum (A) Signup and view all the answers

What triggers depolarization and contraction in the ventricles of the heart?

Action potential from SA node (B) Signup and view all the answers

What is the primary function of hemoglobin in the transport of oxygen?

To bind oxygen molecules for transport in red blood cells (A) Signup and view all the answers

How does a decrease in pH affect the affinity of hemoglobin for oxygen?

It decreases the affinity of hemoglobin for oxygen (A) Signup and view all the answers

Which of the following statements about fetal hemoglobin is true?

It has a higher affinity for binding oxygen compared to adult hemoglobin (C) Signup and view all the answers

What is the primary role of carbonic anhydrase in the transport of carbon dioxide?

To catalyze the formation of carbonic acid from carbon dioxide and water (D) Signup and view all the answers

What happens to bicarbonate ions (HCO3-) produced in red blood cells during the transport of carbon dioxide?

They are transported out of the red blood cells (A) Signup and view all the answers

What happens to oxygen binding to hemoglobin when there is a high concentration of carbon dioxide?

Less oxygen binds to hemoglobin (C) Signup and view all the answers

What is the primary function of antidiuretic hormone (ADH) in regulating urine volume?

It increases the permeability of the distal tubule and collecting ducts to water, leading to more concentrated urine. (A) Signup and view all the answers

What is the role of the renin-angiotensin-aldosterone system (RAAS) in regulating blood pressure and fluid balance?

It increases sodium and water reabsorption in the kidneys, leading to increased blood volume and blood pressure. (D) Signup and view all the answers

What is the primary function of the central nervous system?

It is responsible for processing sensory information and initiating motor responses. (C) Signup and view all the answers

Which of the following statements about the renin-angiotensin-aldosterone system (RAAS) is correct?

Angiotensin II causes vasoconstriction of blood vessels and stimulates the release of aldosterone. (B) Signup and view all the answers

What is the primary function of the brain in the central nervous system?

It is responsible for processing sensory information and coordinating higher cognitive functions. (C) Signup and view all the answers

What happens when there is an excess of water in the body, leading to a decrease in extracellular fluid osmolarity?

Antidiuretic hormone (ADH) secretion decreases, leading to more dilute urine. (C) Signup and view all the answers