Terms in this set (83)
Non-Penetrating; will not enter cells; stays in the ECF
Penetrates cell but once inside is phosphorylated and becomes non-penetrating
The number of osmotically active particles (ions or intact particles) per liter of solution
freely penetrating, moves back and forth between ECF and ICF until [urea] equal. *(not until amounts are equal)
Loss of hypo osmotic fluid
Decreased ICF volume, ECF solute, ECF volume, TBW volume, TBW solute
No change in ICF solute
Loss of iso osmotic fluid
Decreased ECF solute, ECF volume, TBW volume, TBW solute
No change in ICF volume, ICF solute, Osmolarity
Is glucose higher outside most cells?
Yes, because most cells metabolize glucose.
Is CO2 higher outside cells?
No, CO2 is higher inside cells because CO2 is produced by metabolism
Which molecules are in greater concentration outside of the cell?
Na+, Ca2+, O2, Glucose
Which molecules are in greater concentration inside the cell?
Which molecules can move by simple diffusion?
Gases (water has limited movement across lipid bilayer and is always referred to as osmosis)
Movement of Na + from ECF into cells...
moves through a water-filled channel because it follows an electrochemical gradient
Movement of Ca2+ from ECF into cells...
Active transport because it moves against a concentration gradient
Example of Upregulation
Usually occurs when a signal molecule is present in unusually low concentrations
"increase in protein number or binding affinity that increase the response of the target cell"
EX: In type 1 diabetes, insulin levels are LOW, therefore target cells may use up regulation in an attempt to keep a normal-level response. More receptors make the target cell more responsive to whatever neurotransmitters are present.
Which does not require ATP?
Diffusion, which includes simple diffusion and facilitated diffusion.
Molecules go through lipid bilayer freely.
This includes non polar molecules such as lipids (steroids and steroid hormones)
Mediated transport that requires a membrane protein.
Ions --> require channels
Sugars --> require carrier proteins
Which does require ATP?
acts on same cell that secreted it
an example of local communication
secreted by one cell, diffuses to adjacent cells via interstitial fluid
an example of local communication
Example: Histamine. The chemical released from damaged cells. When you scratch yourself with a pin, the red, raised wheal that results is due in part to the local release of histamine from the injured tissue. The histamine acts as a paracrine signal, diffusing to capillaries in the immediate area of the injury and making them more permeable to white blood cells and antibodies in the plasma.
Can a molecule act as both an autocrine and paracrine signal?
Which membrane is the Apical membrane?
Luminal Membrane - because the apical membrane faces the lumen of the intestine or kidney
Where would you find the Na+/H+ co-transporter?
On the Luminal Membrane because H= is secreted into the lumen.
What kind of transporter is the Na+/h+ co-transporter?
How does the Na+/K+ ATPase pump function?
it pumps 3 Na+ out of the cell, and 2 K+ into the cell, keeping ICF Na+ concentration low.
Inside = -70 mV
Outside = 0 mV
-Because of the Na+/K+ ATPase
So sodium is high outside, low inside
and potassium is low outside, high inside
How does the Na+/Glucose Symporter function?
It brings glucose into the cell AGAINST its concentration gradient using energy stored in the Na+ concentration gradient
transfers glucose to ECF by facilitated diffusion
Secondary/Indirect active transport
1.Active transporter of X
2.Sets up gradient fro X
3.X binds to 2nd active transporter for Y
4. Y moves against its [ ] gradient
Ex: Na+/Glucose transporter (X=Na+)
-You create a concentration gradient of one thing in order to move something else inside
Characteristics of mediated transport
Saturation: # of molecules can squeeze in per time
What does the diffusion rate across a cell membrane depend on?
Membrane thickness (because a thicker membrane will mean molecules have to travel further and thus have a slower diffusion rate)
Lipid-solubility of molecule (because if the molecule is not lipid soluble (like a steroid hormone) it will need assistance traveling through the membrane)
Available surface area (because if there is very little area for a large amount of molecules to go through, then that will slow down the flow, as opposed to the same amount trying to go through a larger area).
Fick's Law of Diffusion across a membrane
Rate of diffusion = surface area x concentration gradient x membrane permeability.
Flux is different. The flux of a molecule across a membrane depends on the concentration gradient and the membrane's permeability to the molecule
Isotonic Standard IV solutions
-Normal Saline (0.9% NaCl)
-D5Normal Saline (5% dextrose in normal saline)
Hypotonic IV solutions
-D5W (5% dextrose in water)
-1/2NS (0.45% NaCl)
Inward rectified potassium channel (IRK)
variable-strength signals that travel over SHORT distances and LOSE strength as they travel through the cell.
These are used for short-distance communication
Analog. It fades. A large stimulus causes a strong graded potential, and a small stimulus results in a weak graded potential.
sub threshold at trigger zone
A graded potential that is not strong enough to trigger an action potential.
It does not initiate an action potential.
Supra threshold at trigger zone.
A graded potential that is still above threshold by the time it reaches the trigger zone, so an action potential results
Creates an action potential.
very brief, large depolarizations that travel for long distances through a neuron without losing strength.
Function is rapid signaling over long distances, such as from your toe to your brain.
All or none. Digital signal. 0 or 1. Yes or no.
inside of membrane becomes less negative.
graph deflects upward.
Muscle and Neuron cells: Excitable, able to make them change closer to zero.
Na+ entry into cell is depolarizing because Na+ has a positive charge, thus making inside of membrane less negative/more positive.
Inside of membrane becomes more negative. Graph returns to resting.
Epithelium and connective cells: inside is more negative than outside.
membrane becomes more negative than resting.
Cl- entry into cell is hyper polarizing because it makes membrane potential become more negative than resting potential.
K+ exiting is also hyper polarizing because inside is becoming more negative/less positive by the exit of a positive ion.
Voltage Gated Na+ Channel
Has an activation gate that opens rapidly and an inactivation gate that is slower to close
-Does not depend on neurotransmitters to ask it to open. Instead, when inside becomes positive enough (threshold reached) activation gate opens.
a.) at resting membrane potential, activation gate closes channel
b.) depolarizing stimulus arrives at channel, causes activation gate to open.
c.) Na+ enters cell (further depolarizing the inside of the cell, starting a positive feedback loop)
d.) inactivation gate closes (they are the outside interventions that stops the positive feedback loop) & Na+ entry stops
e.) depolarization (caused by K+ leaving the cell) resets two gates to original positions
This channel initiates action potential in axon hillock
Positive Feedback Loop
Response reinforces the stimulus. Triggers vicious cycle of ever-increasing response.
2 examples are:
1) Blood clotting
2) Giving Birth --> Uterus Smooth muscle contraction --> signal to brain --> signal back to uterus to increase contraction/frequency --> hurt / cervix dilation --> baby!
Negative Feedback Loop
a feedback loop that opposes the stimulus in an attempt to reach homeostatic balance
A signal molecule in the interstitial fluid binds to a receptor on the cell membrane, triggering an intracellular cascade. Which function of the cell membrane does this scenario illustrate?
enables cell to recognize and respond to external environment
Such a receptor that initiates an intracellular cascade when its ligand binds is formed by
a transmembrane (membrane-spanning) protein
The ECF domain of a membrane protein binds a hormone whereas the ICF domain is a kinase that phosphorylates intracellular proteins on specific residues. This membrane protein is a
Channels found in cells in the walls of the carotid artery and the aorta respond to stretch. These channels are described as
A molecule such as glucose crosses membranes via
facilitated diffusion (carrier-mediated transport)
Functions of the spinal cord
reflex and signal transduction
Athletes --> gymnasts --> very well developed cerebellum for balance beam landing.
-Easily influenced under ethanol (alcohol). --> When cerebellum isn't working because of ethanol, you start to move unnecessarily (drunk people)
Thalamus (inside the diencephalon)
This is like the train station.
It is an integrating center and relay station for sensory and motor information.
In the back of the head.
Corpus callosum helps left and right brain talk to each other so that you never feel like you have two brains that disagree with each other.
Overlapping visual field (predatory) left occipital lobe responsible for right visual field.
Right visual cortex on occipital lobe is responsible for left visual field
In between frontal and occipital at the top
Functions : Sensory
Sensory information from skin, musculoskeletal system, viscera, and taste buds.
This is where homunculus comes from. More sensors in lips.
Body info, touch, sense, temp.
Functions: Motor --> Skeletal movement
Every time you decide to move your finger, motor area neurons fire.
The Prefrontal Cortex
Reasoning and decision making
(high level reasoning, takes about 30 years)
-Phineas P. Gage Example
Region of cerebral gray matter involved in control of voluntary movement.
Responsible for Parkinson's Disease
Uses Dopamine to control the motor cortex
3 major regions of the gray matter
cerebral cortex, basal ganglia, and limbic system
The Limbic System
More than one brain area
-includes the amygdala, hippocampus, and cingulate gyrus.
responsible for emotion related memory
If damaged : prevents formation of emotion related memory as evidenced by the scared monkey in cage after being shocked or with snake example.
plays a role in emotion
brain area for learning and memory. It's not where you store memory, it's the area required for long-term memory formation
Henry Morrison: grad school 12 years ago (Cheng) serious epilepsy, lose control of body, 4 or 5 times a day, received surgery to remove brain areas (hippocampus) received it in early 30's
They were able to remove his hippocampus, both left and right. --> Successful, no more epilepsy, but he started to feel weird.
He didn't remember new people he had just met (nurses) He lost the ability to form any new memories after the surgery. It's like all his life ended the day of the surgery. Gave himself up for scientific research
Types of Long-Term Memory
Reflexive (Implicit) Memory & Declarative (Explicit) Memory
Recall is automatic and does not require conscious attention
Acquired slowly through repetition
Includes motor skills and rules and procedures
Procedural memories can be demonstrated
Recall requires conscious attention
Depends on higher-level thinking skills such as inference, comparison, and evaluation
Memories can be reported verbally
Synergism (A type of hormone interaction)
Effect of 2 or more hormones on the same parameter is greater than additive (so 1 + 1 = >2)
For example: Epinephrine (which elevates blood glucose 5mg/100mL blood) and glucagon (elevates blood glucose 10mg/100mL blood) present in a target cell at the same time would be expected to elevate blood glucose to 15mg/100mL, but instead elevate it to 22mg/100mL. Their combination yields a result that is greater than additive.
Permissiveness (A type of hormone interaction)
One hormone is needed for another to exert its full effect (first hormone has no direct effect on parameter) (So 1 + 1 = 1)
So the first hormone cannot exert its full effects unless a second hormone is present, even though the second hormone has no apparent action
For example: Maturation of reproductive system. Thyroid hormone alone = no development of RS
Reproductive hormones alone = delayed development of RS
Reproductive hormones w adequate thyroid hormone = normal development of RS
Antagonism (A type of hormone interaction)
hormones have opposing effect (so 1 + 1 = 0)
For example: The regulation of blood sugar by Insulin and glucagon. If sugar is too high it will damage kidneys and weak structures in blood vessels (like the retina --> causing blindness because sugar damages blood vessels in eyes). If it's too low, there won't be enough energy for the brain.
So blood sugar needs to be maintained. Insulin lowers it, glucagon elevates it. Don't need to work on same receptor.
Glands above the kidneys. Part of endocrine organs. Outside part. epithelial tissue
forms the core of the adrenal glands. part of nervous system
When stressed out, is activated by autonomic nervous system (sympathetic), causing the release of stress hormones like epinephrine and norepinephrine, which increase heart rate/blood sugar levels --> Body is ready to fight.
Primary source of steroid hormones
3 major classes of hormones
synthesized from either tyrosine or tryptophan
(depends on individual cases, but T3 & T4 are amines that behave like steroid hormones in that they penetrate the cell membrane)
Examples: Melatonin (derived from tryptophan), catecholamines and thyroid hormones (made from tyrosine)
Catecholamines behave more like peptide hormones (epinephrine, norepinephrine, and dopamine)
Thyroid hormones behave more like steroid hormones
synthesized by linking amino acids
-made in tissues all over the body
-vesicles containing peptides are stored in the cytoplasm of the endocrine cell until the cell receives a signal for secretion.
-At that time, the vesicles move to the cell membrane and release their contents by calcium-dependent exocytosis.
-are water soluble so they dissolve easily in the ECF and can be transported throughout the body
-because they are lipophobic, unable to enter cell --> must bind to surface membrane receptors --> initiates cellular response (signal transduction system)
made from cholesterol
-most are made in adrenal cortex or gonads (ovaries and testes).
-are not stored in the endocrine cell because of lipophilic nature. They are made on demand and diffuse out of the endocrine cell.
boss of autonomic system (sympathetic and parasympathetic)
-has many sensors sensitive to osmolarity.
in center of head
releases many hormones to regulate body health
endocrine system --> epithelium tissue that produces hormones
nervous system --> nervous tissue
has neural connection to the hypothalamus
Oxytocin and Vasopressin --> both go from hypothalamus to posterior pituitary
Deuterium oxide (D2O)
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