Physiology Review Flashcards
Which pairing of an intravenously administered fluid and its effect on both intravascular fluid volume (IV) and extracellular fluid volume (ECV) would be correct in a normal patient?
Tonicity is given relative to normal plasma. Assume a simple 2-compartment model (vascular space [blood/plasma] and extracellular fluid space).
Isotonic (normal) saline; increase in IV; no change in ECV
A 55-year-old man with a longstanding history of alcoholism is found in a coma following ingestion of an unknown substance. Lab results show BUN of 11 mg/dL, serum sodium of 110 mEq/L, and blood glucose of 70 mg/dL, but serum osmolality of 450 mOsm/L. What finding is most expected?
Coma resulted from ingesting a high osmolarity substance
What substance readily diffuses across the cell membrane without facilitation?
Carbon dioxide
What differentiates osmosis from diffusion?
Osmosis seeks to equalize the concentration of solvent
What substance uses osmosis to cross the cell membrane?
Water
What is the primary function of active transporters in the cytosol of a cell?
Regulate cytosolic pH
How does an uncharged molecule move through a membrane during passive transport?
Concentration gradient
Active transport requires energy to move substances against a concentration or electrical gradient. What is the primary source of energy for primary active transport?
Adenosine triphosphate
Primary active transport involves an ATP-powered pump and what other molecules?
Sodium and potassium
What is an example of secondary active transport?
Sodium-calcium antiporter
Diffusion is a mechanism by which molecules are transported across the cell membrane. Several factors can affect the rate of diffusion. Which description accurately explains one of these factors?
Higher temperature increases the rate of diffusion
What is the most common extracellular cation in the human body?
Sodium
When a neuron begins the process of depolarization, what ion’s concentration begins to rapidly increase within the neuron cell membrane?
Sodium (Na++)
What substance is most often transported through the cell membrane via active transport?
Potassium
What electrical signal unique to muscle and nerve cells is created by a change in voltage across the cell membrane?
Action potential
How does a severely low serum potassium affect the cardiac action potential?
Repolarization time is prolonged
Which process triggers an action potential?
Depolarization of the membrane
Action potentials occur in excitable cells (neurons, muscle cells), allowing charged particles to pass through a channel into the cell membrane. What type of ion channel is primarily associated with somatosensation?
Mechanically-gated channel
What structure in the cell membrane contributes most to the hydrophilic outer aspect and hydrophobic inner aspect of the membrane?
Phospholipids
What type of integral protein in the cell membrane is used to pass ions from one side of the cell membrane to the other?
Channel protein
What component of the phospholipid layer is most responsible for the hydrophilicity of the molecule?
Phosphate
If the nervous system is suddenly stimulated by a perceived threat, what change causes an increase in arterial pressure?
Blood volume becomes increased in all chambers
A patient has a systolic blood pressure of 120 mm Hg and a diastolic blood pressure of 70 mm Hg. What is this patient’s pulse pressure?
50 mm Hg (pulse pressure is difference between systolic and diastolic; 120 mm Hg - 70 mm Hg = 50 mm Hg)
Arteriosclerosis, a leading cause of hypertension, affects which variable that influences blood pressure and blood flow?
Compliance
Which vessel is the first to branch off of the aorta, carrying oxygenated blood into systemic circulation?
Coronary artery
What component of the circulatory system carries oxygenated blood from the lungs into the heart?
Pulmonary vein
The vessels in the body are divided into two divisions according to the type of blood they carry. How do arteries differ from veins?
Arteries have thicker and more elastic walls
Unlike most arteries, the pulmonary arteries do not carry oxygenated blood from the heart to the tissues. What other artery shares this characteristic?
Umbilical arteries
What hormone secreted in response to low blood pressure maintains fluid balance in the body by opening aquaporin channels, increasing the water uptake by the kidneys?
Vasopressin
A patient with liver disease presents with ascites. What is the primary mechanism related to edema occurring with liver disease?
Decreased oncotic pressure
A patient presents with lower extremity edema and is found to have a serum albumin level of 2 g/dL (normal: >3.5d/dL) secondary to liver failure.
What force is responsible for the development of this patient’s edema?
Decreased intravascular oncotic pressure
What set of tissues composes human blood?
Plasma, platelets, red blood cells, and white blood cells
What is the main role of neutrophils in the blood?
Destroy bacteria through phagocytosis
What type of blood cell grows from a lymphoid precursor cell?
Natural killer cell
What type of leukocyte is activated in parasitic worm infections and is a marker for this type of infection?
Eosinophil
In an emergency situation, blood from a universal donor can be given. What blood type is reflected in a “universal donor” status?
O-negative
Why is type O negative blood considered a universal donor?
It has no antigens on the outside of the red blood cells
What type of blood type most contributes to the development of erythroblastosis fetalis in pregnancy?
Rh factor incompatibility
ABO/Rh classification of blood indicates the different antigens that are possibly present on the red blood cell (RBC) surface. In a scenario where emergency blood or plasma transfusion is necessary, which blood type would be a universal donor of RBCs and which blood type would be a universal donor of plasma, respectively?
O-, AB+
A 25-year-old healthy Rh-negative woman is pregnant with an estimated gestational age of 3 months (end of the first trimester). An amniocentesis reveals that her fetus is Rh-positive. Her past medical history is significant for a single prior pregnancy, which she remembers was Rh-negative, was carried to term, and was delivered at home. She remembers only that the baby was healthy and can recall no further details.
What is most appropriate in the care of this patient?
Continue routine prenatal care, Rh immune globulin after delivery
What molecule is a naturally occurring anticoagulant?
Antithrombin
Hemostasis is the physiological response that stops bleeding at the site of an injury. What is the function of insoluble fibrin?
Stabilize the blood clot
During trauma or injury, the body initiates the repair of the damaged tissue. What cells are responsible for developing a mesh-like clot to prevent further loss of blood?
Platelets
Factor XII is exposed to endothelial collagen and becomes Factor XIIA, an activated serine protease. A cascade of clotting factors follows and includes factors XI, IX, and X. Which factor displays the highest concentration throughout this progression?
X
What clotting factor specifically involves the common pathway?
Factor II
What clotting molecule is exclusively linked to the extrinsic pathway?
Thromboplastin
Which blood component is a granular leukocyte that produces and releases histamine as part of the immune respnose?
Basophil
Which agranular leukocyte in the blood is responsible for immunoglobulin production?
B lymphocyte
Leukocytes develop antibodies and protect against pathogens and other foreign bodies. What type of leukocyte is phagocytic?
Neutrophil
What molecule secreted by cytotoxic T cells aids in the immune destruction of infected cells?
Perforin
What cytokine is implicated in transplant rejection and can be measured in an individual suspected of having an autoimmune disorder?
Interleukin-6
What type of immune cell participates in B cell differentiation and secretes cytokines necessary for the activation of B cells?
Th2 cells
A scientist wants to develop a new drug to inhibit T-cell proliferation and antibody formation to aid in immunosuppression for patients receiving organ transplants. What molecular component should the drug target?
Interleukin-2
What disease-modifying anti-rheumatic drug (DMARD) is used to treat rheumatoid arthritis?
Methotrexate
What autoimmune disease is treated mainly with thyroid replacement therapy?
Hashimoto’s disease
What autoimmune disease is treated with NSAIDS and Plaquenil or another antimalarial drug?
Systemic lupus erythematosus
What biological agent is used to treat the autoimmune disease rheumatoid arthritis?
Etanercept
What is the movement sequence of the signal in the nerve cell?
Dendrites, cell body, axon, axon terminals
During a neuron action potential, what is the millivolt potential across the membrane when the nerve cell is completely depolarized?
+30 millivolts
At the motor end plate of the neuromuscular junction between the nerve and skeletal muscle, an action potential is created. What part of this process begins the formation of the action potential?
Sodium enters the cell
Some postsynaptic receptors cause excitation upon activation, where others cause inhibition. What is associated with excitation?
Decreased conduction through chloride channels
The corticobulbar tract sends ipsilateral signals from the motor cortex as descending pathways originating in the Betz cells. Where do these terminate?
Brainstem
Which motor spinal tract sends fibers from the cortex of the brain to control the muscles of the appendicular skeleton?
Lateral corticospinal tract
What motor tract sends signals to the spinal cord to control the muscles of the trunk?
Anterior corticospinal tract