Exam1ObjectivesBased Flashcards
How do you calculate the total body water?
Multiply the weight (kg) by .6 (or 60%). The amount of water is inversely related to fat. Total body water = ~60% BW
How do you calculate intracellular and extracellular fluid?
Intracellular fluid = ~40% of BW Extracellular fluid = ~20% of BW = 16% interstitial fluid = 4% plasma
How do you calculate blood volumes?
Blood volume = 6-8 % (60-mL/kg) BW
What are the characteristics of cell membranes?
They are not freely soluble to all solutes. They have selective permeability They are composed of lipids and proteins
Explain the phospholipid and protein component of cell membranes
The phospholipid component: Glycerol backbone (water soluble) Fatty acids tails (lipid soluble) Forms a lipid bilayer making it amphipathic The protein component includes -Integral proteins -Peripheral proteins
Summarize how transport can occur across cell membranes
Transport across the cell membrane can occur with or without the use of ATP, but it is specific. -Down the electrochemical gradient is called SIMPLE DIFFUSION -Against the electrochemical gradient: Primary transport (direct input of energy) Secondary transport (indirect input of energy)
Explain the features of carrier-mediated transport and list the transport systems that use them
- Saturation: carrier proteins have limited binding sites (rate of transport highest at lower solute concentration ) 2. Stereospecificity: Binding sites are specific 3. Competition: carriers may recognize and bind chemically-related solutes
Explain five factors that contribute to the rate of simple diffusion
- Concentration gradient: driving force 2. Partition coefficient: based on lipid solubility of solute 3. Diffusion coefficient: based on the size and viscosity of solution 4. Thickness of membrane 5. Surface area: greater surface area =higher diffusion rate Consequences of ion diffusion: 1. Potential difference created 2. Diffusion potential created
Describe the principle of primary active transport and list three examples
the solutes movement occurs against the concentration gradient and requires ATP. 1. Sodium/potassium ATPase pump: present in membranes of ALL CELLS 2. Calcium ATPase pump: (PMCA) present in muscle cells 3. H+/K+ ATPase pump present in stomach 4. H+ ATPase present in kidney
Describe the principle of secondary active transport and explain two types of secondary transport
Secondary transport used the energy (concentration gradient) created from the action of one pump (e.g., Na+/K+ ATPase pump) to drive a different pump -Co-transport (symport): all solutes are transported in same direction. ex: the sodium is used in the secondary pump to bring glucose in against its concentration gradient inside the cell. -Counter-transport (antiport): the solutes moved in the opposite directions. ex: Calcium and sodium exchange
What are the major ions in ICF? cations/anions
cation: K+ anion: organic phosphates and proteins
What are the major ions in ECF?
cation: Na+ anion: Cl- and HCO3-
How is electronegativity in ECF and ICF maintainted?
When Osmolarity is same in both compartments
What is the plasma volume of a 35 kg dog?
35 (.04)= 1.4 or 1400 mL/kg
What does the movement of solutes across the cell membrane depend on?
- Concentration gradient: driving force 2. Partition coefficient: based on lipid solubility of solute 3. Diffusion coefficient: based on the size and viscosity of solution 4. Thickness of membrane 5. Surface area: greater surface area =higher diffusion rate
What does the movement of solutes across the cell membrane depend on?
- Concentration gradient: driving force 2. Partition coefficient: based on lipid solubility of solute 3. Diffusion coefficient: based on the size and viscosity of solution 4. Thickness of membrane 5. Surface area: greater surface area =higher diffusion rate
What are aquaporins?
Specialized channels that carry water into the cell during osmosis
What are aquaporins?
Specialized channels that carry water into the cell during osmosis
Explain the principles of osmosis, osmotic pressure, and hydrostatic pressure.
Osmosis is the flow of water across the cell membrane and it occurs due to PRESSURE DIFFERENCES= OSMOTIC PRESSURE. It does not required carriers nor energy. Osmotic pressure is the tendency of the solution to pull in more solvent Hydrostatic pressure is the pushing pressure exerted by the stationary fluid at equilibrium (stops osmosis)
Describe osmotic and hydrostatic pressures as they relate to fluid movement into and out of blood vessels
Osmotic pressure: the pressure needed to stop osmosis It depends on the number, not the mass of molecules: P= n (number of particles)/volume
Define and contrast osmolarity and osmolality
Osmoles: osmotic pressure caused by a mole of molecules in water. Osmolality: the amount of force per volume measured in mOsm/L or mmol/kg. Normal plasma osmolality ~290 mOsm/L
Define osmotic balance and tonicity
Isosmotic: equal osmotic pressure Hyperosmotic: solution with higher solutes (number of molecules) exerting more pressure Hypo-osmotic: solution with lower concentration, exerts less pressure
Explain the term “oncotic pressure” and how it relates to fluid movement into and out of blood vessels
Oncotic pressure is a form of osmotic pressure specifically exerted by proteins, mostly albumin, white blood vessels. It tends to pull water into blood vessels (necessary to maintain flow) Hydrostatic pressure = opposes osmotic pressure (pulls water out of vessels) Decrease in blood oncotic pressure = edema (fluids coming out of vessels into interstitial)
1.Define diffusion potential and equilibrium potential and describe the conditions necessary to establish these potentials.
Diffusion potential is the negative or positive potential difference created by charged ions moving down the concentration gradient across the membrane. Electrophoresis: proteins inside the cells are anions. The two forces causing ions to move are: 1. Concentration gradient 2. Electrical gradient Equilibrium potential: the protein component inside and the non-protein component outside the cell balance out the charges
Explain how a resting membrane potential (RMP) is generated and list the ions contributing
V= I x R (Ohm’s law)
Voltage is potential
I= current (flow, kenetic)
R= resistance
G= conductance (ability to move or flow)
- Selective permeability of the membrane for Na+ and K+
- The Na+/K+ ATPase pump sets diffusion potential (3 Na+ per 2 K+)
The nerve impulse is unidirectional and they start at the AXON HILLOCK.
During the resting state (polarized) the inside of the cell is negative because K+ is slowly leaking out of the cell (K+ efflux) ~-70 mv.
During active state (depolarization) the inside is positive because Na+ rushes in. ~ +40 mv.
During repolarization it goes too far ~ -80mv. Inside K+ pump allows too much in.
The membrane potential is created by enough stimuli to reach/activate the threshold. If it doesn’t (subthreshold) it remains in a local excitatory state.
.Define the terms depolarization, hyperpolarization, inward and outward current, threshold potential, overshoot, undershoot, absolute and refractory periods
Hypokalemia: less K+ outside the cell = hyperpolarization (K efflux higher and inside of cell more negative)
Hyperkalemia: More K outside = less efflux, which cause the cell to be more positive inside bringing closer to threshold
Refractory periods occur when the excited cell can not produce a AP because it needs to recharge.
Absolute refractory period (ARP): period of time during which a 2nd AP can’t occur no matter how strong the stimilus is because the Na+ channels are closed (inactivation). It lapses from the firing level to the early part of repolarization
Relative refractory period (RRP):
Identify the events of an action potential (AP) on a graph and describe those events
AP is the rapid changes in the membrane potential following stimulation of the nerve by threshol stimulus.
At rest the neuron becomes excited by stimuli. If the threshold is met then it depolarizes (firing level). After depolarization it reaches a peak (spike potential 2ms) Na+ infflux fast two door gated channels.
Repolarization is rapid but then slower K+ channels only one door, open and Na+ channel closes.
Hyperpolarization takes a longer time to reach RMP again.
The non-gated K+ channels (slowly leaking) then inward K+ in hyperpolarization. The voltage gated K+ overshoots
The latent period happens before stimuli reaches threshold.
1.Explain the difference between electrical and chemical synapses, and define gap junctions
Millions of neurons within the body must communicate with another or effector cells via synapses that allow information to be filtered and integrated.
- Electrical synapses: have gap junctions and ion channels (a.k.a. connexons) that connect two adjecent cells. This type os synapse is common in cardiac and smooth muscle. electrical synapses allow for quicker communication than chemical synapses, coordination of larger number of cells, and two-way transmission between two cells.
- Chemical synapses: there is a physical separation between two cells (synaptic cleft). The action potential only propagate along membranes it can’t cross the synaptic cleft. The Action potential is converted into a chemical signal when it reaches the Pre-synaptic end bulb. It uses neurotransmitters to cross the cleft.
AP arrives at the presynaptic axon terminal, then the voltage gated Ca ions open, which triggers neurotranmiters vesicles to fuse with the cell membrane at active zones. Exocytosis occurs and the neurotransmitters flow into the cleft. They bind to ligand-gated Na channels (postsynaptic densities) causing the channels to open. Na+ enters the cell leading to depolarization and if it reaches threshold an AP is genetared in the postsynaptic neuron.
What is summation? ARP, RRP and local response?
When you add stimulus, more and more until it increases the magnitude of the local response.
The firing level is not achieved during summation (local response). However, in AP all or nothing principle and the firing level is reached. Anesthesia blocks AP maintaining the neuron completely depolarized (negative, further away from firing level).
What factors contribute to nerve excitability?
Calcium (Hypercalcemia)
Sodium
Potassium
Sodium potassium pump
Anything that decreases nerve excitability is a membrane stabilizer ex: administering calcium, calcium gluconate to stabilize the member of the heart.
Glucose takes five things into the cell to produce energy
Describe the general design and function of the nervous system
The components of the CNS:
- Brain: cerebrum, cerebellum, and brains stem
- Spinal cord: cervical, thoracic, lumbar, sacral, coccygeal.
The central nervous system receives sensory information, integrates it and process it. It decides if motor response is necessary and will occur. Not all sensory stimuli require a motor response.
CNS: Integrations (conscious & unconscious)
PNS: Integration (conscious & unconscious) Sensory output, environmental stimuli and motor output
The components of the PNS:
- Spinal nerves containing sensory and motor function
- Sensory (afferent) neuron: convey information from the sensory cells to the CNS
- Motor (efferent) neurons: conveys information from CNS to effectors
EFFECTOR: can be a cell, organ, or tissue that responds to stimulus
NERVE: is abundle of neuron axons in the PNS that convey information from a particular source.
BOTH CNS and PNS contain sensory and motor components
The CNS also contains integrative components
Describe the general anatomic structure of the spinal cord and the divisions and roles of each major area
What does SS, VS, VM, and SM stand for?
The spinal cord extends from just the caudal medulla to vertebral body L6 (in the dog). The center line devides the Dorsal (sensory) and Ventral (motor) functions.
Gray matter (inside): Interneurons and motor neurons. Butterfly or “H” Shape. It contains 2nd order sensory relay neurons in the dorsal horn and motor neurons in the ventral and intermediolateral horns.
Dorsal horn: Contains interneurons (sensory)
Lateral horn: Contains motor neurons
Ventral horn: Contains motor neurons
White matter (outside): surrounds the gray matter.
Dorsal root: It is sensory. Contains dorsal root ganglion, Somatic sensory neuron, and Visceral sensory neuron.
Ventral root: It is motor. contains Somatic motor neuron, Visceral motor neuron
Dorsal root ganglion: Collection of SOMAS in the peripheral nervous system, which is outside the spinal cord and CNS.
Three funiculi: ventral funiculus, lateral, and dorsal funiculus. They contain ascending and descending UMN (upper motor neurons) repectively.
Tracts or Axon bundles
Note: Autonomic and somatic are both motor bc they are on the ventral side. The somatic will not relay in a ganglia (Ganglion is a relay station for distribution and regulation), it will go straight to muscle bc you need to run to save your life, so there can’t be any delay. However, autonomic will relay in a ganglia, which devides in Pre-ganglionic and Post-ganglionic Fibers.
Describe the embryologic origen of the CNS and PNS
The CNS originates from the NEURAL TUBE
The PNS originates from NEURAL CREST
We started as a bilamminar embryo. The inner cell mast is called embryoblast, which forms the embryo.
The embryoblast will form into two layers: Epiblast is what contributes to the main embryo and form a primitive streak.
The Trilamminar embryo consist of:
The primitive streak, which has an endoderm, mesoderm, and ectoderm layer.
The Neuroectoderm originates from the Ectoderm and it produces the Neural Tube and the Neural Crest.
Compare and contrast the autonomic and somatic nervous systems
Autonomic Nervous System controls involuntary responses. It is dived into:
Sympathetic: Response system
Parasympathetic :“Rest and digest” system
Somatic Nervous System controls voluntary movements
Compare and contrast the parasympathetic and sympathetic nervous system including: Site of origen in CNS, Organs on innervations, Neural pathways, Neurotrasmitters, Location of SNS vs. PSNS ganglia
The Sympathetic Nervous System Postganglion Neurotransmitters: Norepinephrine, and Ach in salivary glands.
Origen: Lateral Horn Cell of CNS. Thorolumbar region of spinal column.
Relay: Cervical Ganglia (Lateral), where Eye pupillodilation occurs, skin vessoconstriction to reduce bleeding, Salivary glands secretion, which increases thirst, so drinking water cools down your body.
Cervical and upper thoracic (lateral), ß1 and ß2 receptors work on bronchiodilation, cardiovascular increase heart rate, raises blood pressure by constricting vessels except in muscles and coronary artery. No energy wasted in digestion, so blood is taken from GI tract through V.C.
Celiac and Superior. mesenteric (collateral) abdomen, Inferior mesenteric (collateral). The bladder relaxes to hold urine.
Note: Only Adrenal Medulla can produce Epinephrine and Norepinephrine because it has the enzyme PMMT
Describe the SNS regulation of organ response by adrenoceptors including postsynaptic receptor type.
The Sympathetic Nervous System releases NE and Alpha (are less sensitive) and Beta receptors in the smooth muscle (bladder) cause the following:
Cervical and upper thoracic (lateral), ß1 and ß2 receptors work on bronchiodilation, cardiovascular increase heart rate, raises blood pressure by constricting vessels except in muscles and coronary artery. No energy wasted in digestion, so blood is taken from GI tract through V.C.
Celiac and Superior. mesenteric (collateral) abdomen, Inferior mesenteric (collateral). The bladder relaxes to hold urine.
Note: Only Adrenal Medulla can produce Epinephrine and Norepinephrine because it has the enzyme to produce it from NE
