Reflexes and Cell Junctions

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Questions and Answers

Where does erythropoiesis primarily occur in the body?

  • Red bone marrow (correct)
  • Renal cortex
  • Renal medulla
  • Descending Loop of Henle

Which part of the nephron is responsible for reabsorption of Na+ and Cl- from the filtrate into the interstitial fluid?

  • Loop of Henle (correct)
  • Glomerulus
  • Proximal tubules (PCT)
  • Collecting duct

What is the main function of the collecting duct in the kidney?

  • Secretion of ions to maintain blood pH
  • Filtration of small solutes from the blood
  • Production of erythrocytes
  • Reabsorption of water and solutes (correct)

What is the role of plasma in the body?

<p>Contains clotting factors (D)</p> Signup and view all the answers

Which hormone upregulates aquaporins in collecting ducts to increase water reabsorption into the bloodstream?

<p>Aldosterone (C)</p> Signup and view all the answers

What is the function of the descending Loop of Henle in the kidney?

<p>Reabsorb water via aquaporins (B)</p> Signup and view all the answers

Where do megakaryocytes primarily fragment to create platelets?

<p>Red bone marrow (C)</p> Signup and view all the answers

What happens in leukopoiesis?

<p>Production of white blood cells (A)</p> Signup and view all the answers

What is the main function of tight junctions between adjacent epithelial cells?

<p>Prevent the leakage of small molecules and ions (A)</p> Signup and view all the answers

Which reflex involves the spreading of a baby's toes and lifting of its big toe when the sole is stimulated?

<p>Babinski reflex (C)</p> Signup and view all the answers

What is the function of hemidesmosomes in cells?

<p>Connect cells to the extracellular matrix (A)</p> Signup and view all the answers

Which enzyme is responsible for relieving the overwinding of DNA strands during replication by breaking, swiveling, and rejoining DNA strands?

<p>Topoisomerase (C)</p> Signup and view all the answers

What type of immunity involves dendritic cells that are specialized immune cells found in the skin and mucous membranes?

<p>Adaptive immunity (B)</p> Signup and view all the answers

Which reflex is characterized by the baby's head moving toward an object that stimulates its mouth and cheeks?

<p>Rooting reflex (B)</p> Signup and view all the answers

What is the main role of ribosomes in a cell?

<p>Protein synthesis (B)</p> Signup and view all the answers

Which enzyme binds two DNA fragments together by phosphodiester bonds during DNA replication?

<p>Ligase (D)</p> Signup and view all the answers

What would be the primary consequence of a deficiency in antidiuretic hormone (ADH)?

<p>Excessive water loss and increased thirst (C)</p> Signup and view all the answers

If aldosterone levels are low, what would be the expected outcome?

<p>Decreased sodium reabsorption in the kidneys (A)</p> Signup and view all the answers

Which of the following statements accurately describes the relationship between blood pressure, filtration, and reabsorption?

<p>Increased blood pressure increases both filtration and reabsorption (A)</p> Signup and view all the answers

Which condition is characterized by an excess of fluid in the blood plasma?

<p>Hypervolemia (A)</p> Signup and view all the answers

Which division of the nervous system is responsible for the involuntary control of gastrointestinal functioning?

<p>Enteric nervous system (C)</p> Signup and view all the answers

Which division of the nervous system is associated with voluntary control of body movements through stimulation of the skeletal muscles?

<p>Somatic nervous system (B)</p> Signup and view all the answers

Which characteristic distinguishes the parasympathetic nervous system from the sympathetic nervous system?

<p>The parasympathetic nervous system has longer preganglionic fibers and shorter postganglionic fibers (D)</p> Signup and view all the answers

What is the primary function of the sympathetic nervous system as described in the given information?

<p>Increasing various physiological processes in response to danger or stress (C)</p> Signup and view all the answers

What is the primary function of goblet cells in the respiratory tract?

<p>Produce mucus to trap foreign particles (B)</p> Signup and view all the answers

Which type of mutation involves the inversion of a chromosomal segment?

<p>Inversion mutation (B)</p> Signup and view all the answers

Which type of mutation is most likely to accumulate in a species over time through natural selection?

<p>Beneficial mutations (C)</p> Signup and view all the answers

What is the primary function of dendrites in neurons?

<p>Receive action potentials from other neurons (D)</p> Signup and view all the answers

What is the role of myelin sheaths in axons?

<p>Prevent signal loss by insulating the axon (A)</p> Signup and view all the answers

What is the primary function of nodes of Ranvier in myelinated axons?

<p>Allow action potentials to travel quickly through the axon (A)</p> Signup and view all the answers

Which step occurs first in the process of neurotransmission?

<p>Release of neurotransmitters from the presynaptic membrane (A)</p> Signup and view all the answers

Which type of mutation involves a change from a purine nucleotide to a pyrimidine nucleotide, or vice versa?

<p>Transversion mutation (A)</p> Signup and view all the answers

What is the primary function of phosphodiesterase in the cAMP signaling pathway?

<p>To catalyze the cleavage of cAMP to AMP, restoring baseline levels of cAMP (A)</p> Signup and view all the answers

Which of the following statements about positive feedback loops is true?

<p>They encourage deviations from the mean value by amplifying the initial signal (D)</p> Signup and view all the answers

Which of the following statements about the resting membrane potential and action potential initiation is correct?

<p>The resting membrane potential of a neuron is typically around -70mV (B)</p> Signup and view all the answers

Which of the following statements accurately describes the all-or-none phenomenon in action potential generation?

<p>Both threshold and suprathreshold stimuli produce action potentials of the same magnitude (A)</p> Signup and view all the answers

What is the primary mechanism by which summation of impulses occurs in neurons?

<p>Both temporal and spatial summation contribute to the summation of impulses (D)</p> Signup and view all the answers

What is the primary function of myelin sheaths in neurons?

<p>To allow for the saltatory conduction of action potentials (D)</p> Signup and view all the answers

What is the likely effect of increased expression of NMDA receptors in the hippocampus?

<p>Increased likelihood of action potential formation, increasing excitability (B)</p> Signup and view all the answers

Which of the following statements accurately describes negative feedback loops?

<p>They help maintain homeostasis by inhibiting deviations from the mean value (B)</p> Signup and view all the answers

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