General Phys Review Flashcards
Fluid inside the cells of the body
ICF
What is the ICF maintained by
The cell membrane
Fluid outside the cells
ECF
_____ is split into two compartments by the capillary wall
ECF
Fluid around the cells
Interstitial fluid
Fluid portion of blood
Plasma
How is the composition of ICF different
Increased K, protein, magnesium, phosphate
What kind of transport has no energy and uses a gradient
Passive
What are the different types of passive transport
Diffusion
Facilitated difusion
Osmosis
What kind of passive transport uses aquaporins, but doesn’t have to
Osmosis
What kind of transport goes against gradient and requires an enzyme and energy
Active transport
What is an ion channel specific to
Ionic size and charge
Size exclusion of ion channels
A sodium channel can exclude a calcium/potassium ions due to different molecule size
Charge exclusion of ion channels
Interior of channel will be lined with charged amino acids, will prevent like ions from crossing
Ion channels: leaky channels
Always open, some K+ channels and CL- channels
Ion channels: gated channels
Closed until stimulus opens
What kind of channels are ligand, second messenger, voltage, mechanical, light
Gated ion channels
What is the most common leak channel
K+
What direction does Na move if the channel is open
In
What direction does K move is channel is open
Out
What kind of channel remains closed until proper ligand binds?
Ligand gated
This typed of channel is fast to elicit cellular response
Ligand gated channel
Remains open as long as 2nd messenger is around, closes when removed
2nd messenger gated
This type of channel is slower to cause a response, but more diverse effect
Second messenger gated
How voltage gated channels work
- remain closed until membrane potential reaches specific value
- remains open depending on the membrane potential and channel properties
Charge difference across cell membranes due to concentration gradients of ions
Resting membrane potential
Inside of cell is considered ______ compared to outside
Negative
What is the RMP of cell
From -20 to -100mV
What kind of tissue can rapidly change the RMP to send signals and start contraction
Excitable tissu such as muscle and nerve
What changes RMP the most
K+
Charge of ECF
+
Charge of ICF
Negative
What is a major contributor to the RMP?
K+ current through leak channels
What is RMP maintinaed by
K+ leak channels
What is necessary for RMP
Na-K ATPase. Three Na+ out for two in makes inside more negative
-also maintains a large K+ gradient so small flux can occur and generate the RMP
Action potential run through
- rest: negative RMP, K+ flux through leak channels
- local depolarization: stimulation occurs-ligand gated Na channels
- threshold: Nav channels open
- overshoot: Na+ flux
- repolarization: Na+ slows, K+ rises
- hyperpolarization: Na+ slows, K+ rises
- at rest: RMP is re-attained due to K+ leak
Site of communication from one cell to another
Synapses
Electrical synapses
Gap junctions
What are the most common type of synapses
Chemical synapse
Direct connections between cells which allows ions to flow between
Electrical synapses
Creates a syncytium ( bunch of cells acting like one cell)
Electrical synapses
What areas have electrical synapses
Heart, smooth muscle, bladder, where coordinated contraction is required
Excitatory post synaptic potentials
Depolarize cell
- usually the result of opening Na+ or Ca+ channels or closing K+ channels
- glutamate
Inhibitory post synaptic potentials
Hyperpolarize cell
- usually the result of opening Cl- or K+ channels or closing a Na+/Ca+ channel
- GABA and glycine (and sometimes glutamate)
What is the NT effect based on
Receptor
What are the two types of receptors
Ionotropic and metabotropic
This receptor binds channel and opens, faster and fewer response
Ionotropic
Receptor is an ion channel
Ionotropic receptors
Opening and closing depend on binding of ligand
Ionotropic receptors
Examples of ionotropic receptors in the eye
Retinal glutamate receptors are a Na+/Ca2+ channel
Receptors are coupled to an intracellular protein
Metabotropic receptors
How do metabotropic receptors work
Ligand binding activated intracellular protein to alter intracellular 2nd messenger levels
-retinal glutamate receptors are a Gi coupled receptor
What are the 3 main types of metabotropic receptors
Gs
Gi
Gq
Stimulates adenylate cyclase, increases cAMP levels
Gs
Inhibits adenylate cyclase, reduces cAMP levels
Gi
Stimulates phospholipase C, gerenates IP3, increases Ca2+ levels
Gq
What is the special type of metabotropic receptor
Gt: in the eye, acts like Gi, but affects cGMP
What part of ANS generally speeds things up
Sympathetic
What part of the ANS generally slows
Parasympathetic
What does the sympathetic nervous system actually decrease
Gut motility
What does the parasympathetic nervous system actually increase
Gut motility
What NT and receptor is present in all autonomic preganglionic synapses
Acetyl choline and nocotinic
What NT and receptor is in all parasympathetic post ganglionic synapses
Acetyl choline and muscarinic
What is the main NT and receptor in sympathetic postganglionic synapses
NE and alpha 1
What is the main receptor and NT in the adrenal medulla in the sympathetic nervous systme
Epinephrine and B receptors
What is the NT and receptor in they postganglionic somatic (muscles) nervous system
Acetyl choline and nicotinic
Alpha sympathetic receptors in the eye
A1-pupil dilation
A2-reduce aqueous humor formation by reducing B2 release
Beta receptors (symp) of the eye
Beta 2-ciliary relaxation for distance, increases aqueous humor production
Parasympathetic receptors in the eye
- pupil constriction
- ciliary contraction for near
- increase aqueous drainage/ reduce production
- lacrimal secretion
What are gap junctions made of
6 connexins
What are gap junctions used for
Electrical/communication connection, litttle structural support
-just a communication bridge for smooth muscles to create a syncytium
What kind of cellular junctions are structural spot welds
Anchoring junctions
Cell-to-cell anchoring junctions
Desmosomes
Cell-to-ECM anchoring junctions
Hemidesmosomes
These types of cellular junctions make sheets of cells
Tight junctions
What is the tightest cellular junction
Tight junctions
Permeability of tigh junctions
Depends on how tight the cells are held together
What are common areas of tight junctions
Brain eye testes
What are two common types of tight junctions
Zonula occludens
Zonula adherens
In this type of tight junction, the cell membranes touch each other and it is very restrictive. Most movement is transcellular, requiring a protein transporter or ion channels
Zonula occludens
What is a common zonula occludens
Blood brain barrier
This type of tight junction has has a space between the cell membranes. Filtration can occur even though it is still relatively restrictive
Zonula adherens
Where are zonula adherens found
Kidney, blood vessels
What kind of ultrafiltration forces favor filtration
Cap pressure, interstitial osmotic pressure
What ultrafiltration forces favor reabsoprtion
Plasma osmotic pressure nad interstitial fluid pressure
Filtration
Kf*net filtration pressure
- Kf-filtration coefficient, similar to diffusion coefficient
- how permeable the caps are
Composition of ICF
K-, phosphate
Composition of ECF
Na+, chloride
Plasma composition
Proteins
Passive transport
Diffusion, high to low
Active transport
Low to high, can move 2 thing, use ATP and enzymes.
Example of primary active transporter
Na/K transporter
Secondary active transporter
Glucose transporter
You order a blood test, when you receive the lab report, there is a note that the blood was listed when it was drawn. Which of the following readings could be erroneously elevated
Potassium
Which of the following would require energy
Movement of potassium into the cell
Which of the following would cause the membrane potential to become more negative
Closure of sodium leak channels
Which of the following is the most restrictive cellular junction
Tight junction
During aqueous humor production sodium is actively pumped into the anterior chamber. Which of the following will occur due to this
Water follows through aquaporins
Administration of a _______ will increase aqueous humor production
Beta 2 agonist