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Physiology Final Exam
Terms in this set (127)
What is meant by cellular environment?
The daily challenges we face including
environmental temperature changes, exercise stress, diseases, etc. disrupt the
What is the meaning of homeostasis and its purpose?
The body maintains a constant internal environment
Why is a constant internal environment important to a cell?
Maintain life in the cells
Small spherical organelles. Contain enzymes that contain cell debris that has been taken into the cell
Smaller than lyosomes; Function in degradation of molecules such as amino acids, fatty acids, and foreign toxic matter
Dense granules composed of rRNA and proteins that function in protein synthesis
Known as the powerhouse of the cell
Processes molecules synthesized in the endoplasmic reticulum
How does translation differ from transcription?
Transcription is the process whereby a complementary mRNA is produced from DNA template
Transcription: RNA is synthesized from DNA in the nucleus
What is meant by post-translational modification?
The covalent and generally enzymatic modification of proteins during or after protein biosynthesis. Proteins are synthesized by ribosomes translating mRNA into polypeptide chains, which may then undergo PTM to form the mature protein product.
How do amino acids differ from each other?
The R-group and its different chemical characteristics*
What is a peptide bond?
Covalent bonds that hold the amino acids together
What is a carboxyl group?
The carboxyl group is an organic functional group consisting of a carbon atom double bonded to an oxygen atom and single bonded to a hydroxyl group.
What is an anticodon?
A set of three nucleotides that is complementary to an mRNA codon
What is a codon?
A sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.
What is the purpose of a gene?
Act as instructions to make molecules called proteins
What structure makes protein? Describe its parts
What are products?
Different substances as a result of a reaction
What are reactants?
Changing chemical substances entering the reaction
What is anabolic reaction?
Energy is added to the reaction
What is catabolic reaction?
Involves the breakdown of larger molecules into smaller ones
What is a substrate?
A reactant that is altered by enzyme
Where does glycolysis occur?
Breakdown of the glucose in the cytosol to produce ATP and pyruvate
Where does aerobic ATP synthesis occur?
In the inner membrane of the mitochondria
Define parts of the mitochondria
Look in module
What is ATP?
Chemical form of fats, proteins, and carbs
What is glucose?
Primary energy source for cells during the absorptive state. Fats, amino acids, and excess glucose are converted to a storage form of energy molecules
What is the storage form of glucose?
In what organs is this storage form of glucose located?
Liver and skeletal muscle; skeletal muscle is the most common
How does the storage or glucose in the liver and skeletal muscle differ in terms of its use?
How is excess glucose stored in the body?
How are lipids transported in the blood?
Reflects ion concentration inside and out of the cell
Electrical driving forces occur due to an imbalance of positive ions and negative ions on the inside and outside of the cell.
A charged molecule against the across membrane is influenced by both electrical and chemical forces
What are the forms of active transport?
Primary and secondary transport
What are the forms of passive transport?
Simple diffusion, facilitated diffusion, diffusion through ion channels, and osmosis
How do active and passive transport differ?
Active transport requires energy while passive transport does not
What is the difference between primary and secondary active transport?
Primary: Uses ATP, or some other chemical energy source to transport substances.
Secondary: Powered by a concentration gradient, or an electrochemical gradient previously created by primary active transport.
What is the difference between lipophilic and lipophobic in how they cross the cell lipid bilayer?
Lipophilic easily permeate the plasma membrane and lipophobic cannot permeate the membrane
Give an example of lipophilic and lipophobic molecules?
Lipophilic: Steroid hormones
Lipophobic: Peptides and amines
What is a ligand?
Small molecules capable of binding reversibly to proteins
An extracellular that binds to the receptor on the outside of the cell and activates the second messenger
Second messenger systems are a means of transmitting signals from receptors on the cell surface to target molecules.
What is the significant function of the second messenger system?
Amplify the response of the first messenger
What is the CNS?
Primary control system of the body. Responds to sensory receptors throughout the body and the ability to initiate actions
- Brain and spinal cord
What is the PNS?
Is the part of the nervous system that consists of the nerves and ganglia on the outside of the brain and spinal cord.
What are the neurons that carry information toward the CNS?
What are the neurons that carry information away from the CNS and toward the PNS?
What is the difference between the sympathetic and parasympathetic nervous systems?
The sympathetic system speeds up activity (regulate blood flow toward the contracting muscles) and parasympathetic slows down activity
What is the difference between the sensory and somatic nervous system?
The sensory nervous system is controlled by CNS and is used to gain information and the somatic nervous system helps the voluntary skeletal muscles
What pump maintains the resting membrane potential?
What is an action potential?
Waves of depolarization that sweep across the membranes of excitable tissues (nerves and muscles)
Are there more Na+ or K+ leak channels in a cell membrane?
Na+ outside the cell, there is a chemical driving force tending the push Na+ into the cell
What is membrane potential?
Difference in electric potential between the interior and the exterior of the cell
How does the inferior versus the exterior of a cell differ in terms of electrical potential?
The interior of the cell is slightly negative than the exterior of the cell.
What does the permeability of a cell membrane to ions depend on?
Number of ion channels for a particular ion and the ease with which ions move through their specific ion channels
When the resting membrane potential is at -70MV. The inside of the cell is more negative than the outside
When a membrane has a potential more negative than -70MV. The membrane has become more polarized
When the membrane potential is less than -70MV
What channels open during an action potential?
Voltage-gated, ligand gated, and mechanically gated channels
What happens at the axon terminal due to the electrical stimulus?
It becomes depolarized
Describe all the sequence of events beginning with the opening of the calcium channels
Look up in module
What chemical messengers are released from parasympathetic preganglionic neurons?
What chemical messengers are released from sympathetic preganglionic neurons?
Type of sensory receptor neuron in blood vessels that respond to changes in pressure within the cardiovascular system
Sensory nerve cell that responds to damaging or potentially damaging stimuli by sending signals to the spinal cord and brain.
Muscle spindles are sensory receptors within the belly of a muscle that primarily detect changes in the length of this muscle. They convey length information to the central nervous system via sensory neurons. This information can be processed by the brain to determine the position of body parts.
A sensory receptor that receives stimuli from within the body, especially one that responds to position and movement.
What is the difference between actin and myosin?
Actin: A protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells
Myosin: Fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in the motion in other types of cells
Long fibrous molecule that extends over numerous actin molecules in such a way that it blocks the myosin-binding sites in the muscles at rest
The regulatory protein component of the thin filament that binds to calcium, thereby initiating skeletal muscle contraction
A very large fibrous protein that connects thick myosin filaments to Z discs in the sarcomere
Transmit electrical stimuli to the muscle cell that stimulates the release of calcium
The membranous network that surrounds each of the myofibrils
Function as voltage sensors during sarcoplasmic reticulum; transmit signals to ryanodine receptors and the signals the opening of the calcium channels
Receptors that function as calcium channels
What is the interaction between the T-tubules and the sarcoplasmic reticulum?
Transverse tubules (T tubules) penetrate the sarcolemma into the muscle cell's interior. T tubules transmit the wave of depolarization into the muscle cell, stimulating the release of calcium.
What does recruitment mean?
Recruiting different numbers of muscle fibers, recruiting more motor units, and recruiting bigger muscle fibers
The muscle twitches overlap and they superimpose on one another yielding a force greater than that of a single twitch
Repeated stimulation of the muscle
The muscle is generating all the force it can
What is the pulmonary circuit vs. system circuit?
Pulmonary circuit is where blood goes to and from the lungs. Systemic goes to and from the rest of the body
Where is oxygenated blood located?
Pulmonary veins and systemic arteries
Where is deoxygenated blood located?
Deoxygenated blood is pulmonary arteries and systemic veins
In what artery is deoxygenated blood located?
In what vein is oxygenated blood located?
What is meant by isovolumetric contraction?
During the period between the closure of the AV valves and opening of the aortic and pulmonic valves, ventricular pressure rises rapidly without a change in ventricular volume. No ejection occurs and ventricular volume doesn't change; systole
What is meant by ventricular filling? How does this occur?
During Phase 6
What is ventricular ejection?
The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles
What is isovolumetric relaxation?
When intraventricular pressure fall sufficiently at the end of phase four, the aortic and pulmonic valves abruptly close, causing the second heart sound and isovolumetric contraction; diastole
When at rest, where is the greatest proportion of blood stored?
Why are the arteries referred to as pressure reservoirs?
They have an elastic nature that changes based on the pressure and function
What is MAP?
Average arterial pressure during a single cardiac cycle
What is the role of the medulla oblongata?
Help with central chemoreceptors respond to hydrogen changes in the cerebrospinal fluid
What role does carbonic acid play in the transport of carbon dioxide?
When the partial pressure of oxygen and carbon dioxide change at high altitudes, the bicarbonate buffer system adjusts to regulate carbon dioxide while maintaining the correct pH in the body.
Carbonic acid is also located in the cerebrospinal fluid. What role does it play there?
Carbon dioxide does not directly affect the central chemoreceptors, but instead is converted to hydrogen ions and bicarbonate by carbonic anhydrase in the cerebrospinal fluid. Then, the chemoreceptors are activated by the hydrogen ions that are generated as a result.
Pressure of the outside air
- 760 at sea level
- All lung pressures are expressed relative to atmospheric pressure
Pressure inside the pleural space
- Varies with phase of ventilation
- Always less than intra-alveolar pressure during normal breathing due to opposing forces exerted by the chest wall and the lungs that tend to pull in the opposite direction
Pressure within the alveoli
- Equals atmospheric pressure, it is 0
- Varies during phases of ventilation
- Pressure gradient between atmospheric and alveolar that drives ventilation
Difference between the intrapleural pressure and intra-alveolar pressure
- Measure of the distending force across the lungs
What role does hemoglobin play in the transport of oxygen?
Allows the transport of oxygen from the lungs to the rest of the body's cells
Where is hemoglobin located?
In red blood cells
How many oxygens can hemoglobin carry?
What increases the affinity of hemoglobin for oxygen?
Decreased PCO2 and decreased 2,3-DPG
What decreases the affinity of hemoglobin for oxygen?
Increase in temperature, a more acidic pH, increased CO2 production, and increased 2,3-BPG from high altitude/anemia would decrease the affinity.
How is the carbon dioxide level of the blood sensed by the brain?
By the chemoreceptors
What is 2,3-DPG?
Puts hemoglobin into its tense state and promotes oxygen unloading
What ion are the chemoreceptors in the brain sensing?
Where does that ion come from?
Carbon dioxide that does not directly affect the central chemoreceptors
What are the components of juxtaglomerular apparatus?
Renal corpuscle and renal tubule
- Renal corpuscle consist of Bowman's capsule and glomerulus that filter blood
What is the relationship between the afferent and efferent arterioles and the distal convoluted tubule at this point (juxtaglomerular apparatus)
It's designed to monitor both the blood pressure coming into the delicate glomerulus and the osmolarity of the urine as it begins its entry into the collecting duct.
How do the intrinsic and extrinsic controls alter glomerular filtration?
How does the afferent arteriole affect intrinsic and extrinsic controls of glomerular filtration rate? Intrinsic-> Myogenic Regulation- When MAP increases, pressure in afferent arterioles increases, afferent arterioles contracts in response.
Tubuloglomerular Regulation- increase in GFR stimulates afferent arteriole to contract
Extrinsic-> MAP>180mmHg, smooth muscle in afferent and efferent arterioles contracts and the arterioles constrict, which increases the overall resistance of the renal vasculature. This decreases GFR.
Help maintain acid-base balance by secretion hydrogen ions
Respond to hormones that regulate permeability of water and solutes
Modified smooth muscle cells. Contraction of these cells result in a decrease of surface area, which, in turn, decreases glomerular filtration
Special extensions, or foot processes in the epithelial cells of glomerular capillaries
What are aquaporin-2 channels?
The basic job of aquaporin 2 is to reabsorb water from the urine while its being removed from the blood by the kidney.
Where are they inserted in response to ADH?
In the plasma membrnae
What does aldosterone regulate?
Regulate the reabsorption of sodium and the secretion of potassium
What triggers the release of renin?
Macula densa cells sense the effective circulating plasma volume coming through the afferent arterioles. When this volume is decreased, macula densa cells send out signals to the granular cells to secrete renin to the arterioles.
The main triggers are Beta-1 adrenergic stimulation, a decrease in hypo perfusion pressure, a decrease in NACl in the distal tubule sensed by the macula densa.
What is hypernatermia?
An increase in plasma sodium to levels greater than normal, accompanied by water retention and hypertension
What is hyponatremia?
Sodium level lower than normal
What is plasma osmolarity?
Measures the body's electrolyte-water balance; the osmolarity of blood plasma
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