71 Questions
What is the primary function of the genetic message determined by the sequence of nucleotides?
To determine the sequence of amino acids in proteins
What is the site of protein synthesis in the cell?
Rough ER
What is the primary function of the smooth ER?
Lipid production
What is the purpose of the Golgi apparatus in the cell?
To modify and package proteins and lipids
What is the function of lysosomes in the cell?
To degrade cellular waste
What component of the glycolax protrudes outside of the membrane?
Glyco body
Which type of diffusion involves the use of channel proteins?
Facilitated diffusion
Which molecules are unable to pass through phospholipid bilayers?
Charged water-soluble molecules
What process is described as 'cell eating'?
Phagocytosis
What is required for the Na-K ATPase pump to function?
ATP
What occurs during pinocytosis?
Taking up of molecules that form vesicles of ECF
What percentage of the body's water content is found in the ECF?
30%
Which ion is predominantly found in the ICF and contributes to the cytosol?
K
What is the primary determinant of plasma osmolarity?
Sodium
What effectively maintains the intravascular volume in the body?
RAAS and ADH
Which ions have large amounts in the ECF?
Na, Cl, HCO3
Which parameter has a narrow limit for compatibility with life?
Potassium levels
What is the daily water intake for humans on average?
2.5 L
What triggers a decrease in blood pressure according to stretch receptor activity?
Inhibition of the vasomotor center
What is the primary role of the sodium pump in the cell membrane?
Moving three sodium ions outward for every two potassium ions inward
What is one characteristic of protein mediated transport?
Requires energy from ATP
What is a defining feature of sodium ion co-transport (SGLT)?
Glucose is transported with sodium ions
In the gastrointestinal tract and renal tubules, sodium ion co-transport aids in which process?
Active transport of glucose into cells from plasma
Which of the following is not involved in cotransport mechanisms?
Amino acid facilitation
Which of the following proteins is responsible for active transport in the cell membrane?
Carrier proteins
Which component of the cell membrane is most responsible for its nearly impermeable property to water soluble substances?
Phospholipid bilayer
Where are proteins synthesized within the cell?
Rough Endoplasmic Reticulum
What is a characteristic function of integral proteins in the cell membrane?
Spanning the entire bilayer and acting as channels or receptors
Which organelle is involved in lipid synthesis within the cell?
Smooth Endoplasmic Reticulum
Which type of phospholipid is primarily found in the nervous system?
Sphingomyelins
What is the primary function of the glycocalyx on most cell membrane proteins?
Giving cells a negative charge to repel negatively charged particles
What is the correct flow of maintenance fluid for an individual weighing 30 kg?
70 mL/hour
What parameters have narrow limits compatible with life?
Temperature, acid-base balance, potassium
How do negative feedback loops maintain homeostasis?
By counteracting the effect of a stimulus
How do positive feedback loops function in physiology?
They amplify and reinforce changes to the body's internal environment.
What regulates ECF composition?
Kidneys
What is osmosis?
The movement of water molecules from a region of high concentration to a region of low concentration through a selectively permeable membrane.
What is the effect of hypertonicity on RBCs?
RBCs shrink and become more rigid (crenation)
What is the intravascular residency time for isotonic solutions?
20-30 mins
What impact does hypertonic solutions have on systemic blood pressure and ICP?
Increase systemic blood pressure but decrease ICP
Which bodily compartment contains the majority of the body's water?
ICF
What are the predominant ions found in the Extracellular Fluid (ECF)?
Sodium and chloride and bicarbonate
What are the predominant ions found in the ICF?
Phosphate and potassium and magnesium
What quality of ion distribution creates a voltage difference across membranes?
Asymmetric distribution
What percentage of the body is comprised of blood?
5-7%
What is the distribution of plasma to RBCs in 5L of blood volume?
3 L plasma, 2 L RBCs
What is the total serum concentration of potassium?
3.5-4.5 mmol/L, total concentration 45
What is the normal serum concentration of sodium?
137-142 mmol/L. Total = 58
What is osmotic pressure?
The pressure required to prevent water from flowing into a solution through a semipermeable membrane
What determines osmotic pressure?
The number of solute particles in a solution
What is a normal osmolarity?
290 mmol/L
What ions contribute the most to osmolarity?
Sodium ions (Na+) and Chloride (Cl-)
What is the formula for plasma osmolarity?
Na + Glucose/18 + BUN/2.8
When would glucose and urea contribute to osmolarity?
Hyperglycemia and uremia
What part of the cell membrane faces the ICF and ECF?
Hydrophilic heads
What differentiates integral proteins from peripheral proteins?
Transmembrane domain
What are some of the functions of integral proteins in the cell membrane?
Both A and B
What is a glycocalyx?
membrane carbohydrate or lipid that acts as a receptor and modulates immune activity
What organelle does RNA transfer its genetic message to for protein synthesis?
Ribosome
What is the Golgi apparatus the site of?
Glycosylation and phosphorylation
Where are lysosomes produced?
Golgi apparatus
What is the role of lysoferrin?
Regulation of iron homeostasis
What are peroxisomes?
an organelle that contains oxidase to form hydrogen peroxide to oxidize substances
What is the role of the inner layer of mitochondria?
To house mitochondrial DNA and serve as the reservoir space for protons created during electron transport
What is the cell membrane selectively permeable to?
water, gas, fat soluble substance, O2, and CO
What molecules move through facilitated diffusion across the cell membrane?
Glucose and amino acids
What is the role of the sodium ion cotransport system?
To transport sodium ions with another substance
What is the difference between a symporter and an antiporter?
A symporter transports two molecules in the same direction, while an antiporter transports them in opposite directions.
What occurs in protein-mediated transport?
A type of active transport where specific molecules are transported against a concentration gradient
Of the following, which is transported into cells by facilitated diffusion?
Amino acids
What is the largest source of fluid loss on a daily basis in the form of?
Urine
Study Notes
Cell Structure and Function
- Cell membrane: composed of lipid bilayer, phospholipids, sphingolipids, cholesterol, and proteins
- Phospholipids: lecithins, sphingomyelins, amino phospholipids
- Proteins: integral (permanently embedded, span entire bilayer) and peripheral (temporarily associated, do not fully span)
- Integral proteins: receptors, channels, carrier proteins
- Peripheral proteins: attached to integral proteins, act as enzymes or controllers for transport
- Structural proteins: microtubules
- Enzymes: various functions
Cell Membrane Transport
- Simple diffusion: through phospholipid bilayer
- Facilitated diffusion: through channel protein or carrier protein
- Charged water soluble molecules and ions do not pass through membrane
- Osmosis: through aquaporins or phospholipid bilayer
- Endocytosis: taking up of particles by cell
- Exocytosis: release of particles
- Na-K ATPase pump: requires ATP, attaches ATP, and pumps 3 sodium ions out and 2 potassium ions in
Ion Channels and Transport
- Ion channels: allow specific ions to pass through membrane
- Protein-mediated transport: includes ATP and glycoprotein
- Transported against concentration gradient
- Requires energy from hydrolysis of ATP
- Sodium ion co-transport (SGLT): glucose can't move by itself, transported with sodium ions
Organelles and Functions
- Nucleus: contains genetic material
- Rough ER: site of protein production
- Smooth ER: site of lipid production
- Golgi apparatus: storage depot for lipids and proteins, site of glycosylation and phosphorylation
- Lysosomes: garbage disposal, filled with hydrolytic enzymes
- Mitochondria: site of energy production, 2-layered with inner layer housing mitochondrial DNA
Body Fluids and Composition
- Water: most abundant constituent of the body (60% in men, 50% in women, 70% in neonates)
- ECF: 30% of body's water content, contains plasma and interstitial fluid, large amounts of Na, Cl, HCO3
- ICF: 70% of body's water content, contains K, Mg, PO4, and cellular components suspended in cytosol
- Osmosis: diffusion of water from low concentration of solute to high concentration of solute
Maintenance of Cell Volume and Osmosis
- Controlled by movement of K-Na by energy-dependent ATPase pump
- Osmotic pressure: pressure required to prevent continued movement of water
- Osmolarity: concentrations of solutes, primarily determined by sodium concentrations
- Solutions: isotonic, hypertonic, hypotonic
Cell Functions and Processes
- Cell consumes O2 and produces CO2
- Cell contains and is surrounded by fluid
- Microbiota: outnumber human cells and are generally beneficial
- Cell structure and function: proteins made in rough ER, lipids made in smooth ER, nucleolus does not have a membrane
Lesson on basic physiology
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