Midterm 1: Lectures 1-6 Flashcards
Define: Physiology
study fo the function of living organisms, mechanisms of controlling internal environments regardless of external environments, and tries to explain physical and chemical factors of normal function and disease
Define: Homeostasis
the maintenance of relatively stable conditions within the internal environment, regardless of the external environment
Define: Negative Feedback system
decreases the production of something
Define: Positive Feedback system
increases teh production of something
Define: Extracellular fluid
makes up the internal environment, divided into interstitial fluid and plasma
What percent of teh total body water do each of these make up?
ICF:
Interstitial fluids:
Plasma:
67%
- 4%
- 6%
What is the distribution of Na like in and around the cell?
greater concentration outside the cell than inside, therefore wants to diffuse into cell
What is the distribution of K like in and around the cell?
greater concentration inside the cell than outside, therefore wants to diffuse out of the cell
What is the distribution of Cl like in and around the cell?
greater concentration outside the cell therefore wants to diffuse in
What is the distribution of Ca like in and around the cell?
greater concentration outside the cell, therefore wants to diffuse in
Define: Golgi Apparatus
packages proteins from the rough ER into membrane-bound vesicles
Define: Secretory Vesicles
transport proteins to the cell membrane for release to extracellular environment
Define: Storage Vesicles
store contents within the cell
Define: Ribosome
dense granules of RNA and protein, manufacture from amino acids under the control of DNA (either are fixed ie attached to the ER or free)
Define: Lysosome
storage vesicle, produced by the Golgi apparatus, act as the digestive system of the cell
Define: Mitochondrion
generates ATP, the powerhouse of the cell, can replicate without mitosis to meet energy needs
Define: Endoplasmic Reticulum
continuation of cells nuclear membrane, sit of synthesis, storage and transport of protein and lipid molecules
Define: Cell Membrane
main function is to regulate passage of substances in and out of the cell
Define: Centriole
cylindrical bundles of microtubules, responsible for directing movement of DNA in mitosis
Define: Nucleolus
dense body in cell nucleus containing specific DNA that produces RNA in ribosomes
Define: Cholesterol Molecule
in non-polar lipid layer, helps make the membrane impermeable ot some water soluble molecules, also helps keep the membrane flexible over a wider temperature range
Define: Enzymes
act as catalysts for certain reactions immedaiately inside or outside the membrane
Define: Structural Proteins
generally attached to the inside, support adn strengthen membrane, some anchor cell organs to intracellular side
Define: Carbohydrate Molecule
form a protective layer (glycocalyx) that is important for immune response and recognition of other cells in the body
Define: Membrane Spanning Protein
span whole width of the bilayer, act as gates or channels that control movement of certain substances in or out of the cell
What are the 5 membrane proteins?
- receptors
- enzymes
- ion channels
- membrane-transport carriers
- cell identity markers
Whate are the 4 diffusion factors?
- size of protein channels
- charge of molecule
- electrochemical gradient
- number of channels
What are the requirements for facilitated diffusion?
- water soluble substances that cannot diffuse through the bilayer and are too large for protein channels
- does not require energy
- it is limited by the number of available proteins
- shows chemical specificity
- can be competitively inhibited
What are the requirements of active transport?
- requires protein carriers
- can be saturated, show chemical specificity adn competetive inhibition
- uses energy
What are the requirements for osmosis?
- specific pores
- semipermeable membrane
what are the 3 things that affect osmosis?
- permeability of membrane
- concentration gradients
- pressure gradient
Define: Isotonic Solution
same concentration as normal body cell
Define: Hypotonic Solution
lower concentration compared to body cell, causes osmosis of water into the cell (swelling)
Define: Hypertonic Solution
higher concentration compared to body cell, causes osmosis of water out of the cell (shrinking)
Define: Resting Membrane Potential
minute excess of negative ions build up on teh inner surface of the membrane and positive ions build up on teh outside creating an electrical potential difference across the membrane
Define: Equilibrium Potential
electrical potential that must be applied to the inside of the cell to stop the movement of ions down its concentration gradient
Define: Cell body/soma
control center, contains nucleus and directs cell activity
Define: Dendrites
thin, branching processes, increase surface area to communicate with more neurons, brings in cell signals
Define: Axon
projection of cell body, carries cell signal in action potential, may or may not be myelinated
Define: Myelin Sheath
presence of layered phospholipid sheath, insulates axon
Define: Node of Ranvier
unmyelinated part of axon where changes can occur to speed up cell signal
Define: Collaterals
branching’s of axon at terminal end, increases number of target cells that the neuron can interact with
What is an action potential?
the rapid reversal of the resting membrane
What is teh sequence of an action potential?
- Depolarization (sudden change to more positive value)
- Repolarization (return to normal charge)
- Hyperpolarization (membrane is briefly negative)
Define: Voltage-Gated Channel
found on the axon and are essential to generate action potential, open when cell depolarizes
What are the events that happen at a voltage-gated sodium channel?
- depolarization of membrane
- activation gates open immediately
- Na+ flows into cell, down concentration gradient
- inactivation gate closes adn Na+ can no longer flow into cell and channel cannot open
- channel returns to resting position
- channel is ready to open again
What are the events that happen at a voltage-gated potassium channel?
- depolarization of membrane
- after a brief pause, K+ voltage-gated channels open
- K+ flow out of the cell, down electrochemical gradients
- Gate closes and the channel returns to resting configuaration
- channel is ready to open again
What are the events that happen in an action potential?
- strong depolarization at axon hillock triggers opening of most Na+ voltage-gated channels
- Na+ rushed into neuron, down electrochemical gradient,
- Membrane depolarizes rapidly to +35mV
- Na+ channels become inactivated while K+ channels begin opening
- K+ rushes out of the cell, down electrochemical gradient
- membrane beigns repolarizing back to normal
- K+ continues to rush out fo teh cell and teh membrane hyperpolarizes
- K+ channels begin to close and K+ no longer leaves the cell
- Membrane potential slowly returns to resting value
what is necessary for an action potential to fire?
the depolarizing force from the Na+ moving in must exceed the natural repolarizing forces from K+ moving out and Cl- moving in
What are the 6 steps in propagation of an action potential?
- the inside of the membrane is positive because of the Na+ that have entered the cell
- positive area moves toward area next to it that is negative
- adjacent area of membrane depolarizes
- Na+ channels open
- Na+ depolarizes the region to threshold
- action potential is propagated
What is myelin made by in the peripheral nervous system?
Schwann cells
What is myelin made by in the central nervous system?
oligodendrocytes
What are the events at the neuromuscular junction?
- action potential on motor nerve triggers Ca++ channels to open
- this triggers the release of ACh into the synaptic cleft
- this attaches to receptors in membrane
- Ligan-gated channels open, Na+ entering triggers a local depolarizationn (end plate potential/EPP)
- depolarization of EPP spread to adjacent cell, large amounts of Na+ flow into cell and trigger the action potential
- ACh is broken down to acetic acid and choline by AChE
What are the 3 types of muscle cells?
skeletal, smooth and cardiac
Define: Myofilaments
the contractile units of the muscle cell
Define: Sarcolemma
muscle cell membrane
Define: Sarcoplasmic Reticulum
mesh-like network of tubes containing calcium ions which are essential for conduction
Define: Actin
a globular protein that forms the backbone of thin myofilaments and are contractile proteins
Define: Myosin
bind on to actin as the other contractile protein
What are the 3 regulatory proteins in muscle contractions?
actin/myosin, tropomyosin, troponin
Define: Sarcomere
the region from one Z disk to another, it is the smallest contractile unit
What are the steps in the sliding filament mechanism?
- activation and cocking of myosin head
- formation of myosin-actin cross-bridge
- power stroke, sliding of thin filament over thick filament
- binding of new ATP and breaking of cross bridge
Define: Excitation-Contraction Coupling
an action potential in the cell membrane excites the muscle cell to produce a muscle contraction
What are the steps in excitation-contraction coupling?
- action potential is propagated down t tubules
- calcium is released
- bidning of calcium to troponin
- shifting of tropomyosin to expose active sites on actin
How does muscle relaxation work?
calcium pumps bring calcium back into sarcoplasmic reticulum which requires ATP, this means myosin will be unable to bind because tropomyosin will cover the myosin binding sites when Ca is present
Define: Motor Unit Recruitment
the progressive activation of motor units resulting in a more forceful contraction to match a load increase
Define: Brainstem
controls some of the most basic functions of the body and is made up of the midbrain, pons and medulla oblongata
Define: Medulla
is continuous with the spinal cord
Define: Cerebellum
in the posterior region just above the brain stem, is responsible for coordinated movement
Define: Diencephalon
consists of the thalamus and hypothalamus
Define: Motor Cortex
processes input from skeletal muscles throughout the body, part of the frontal lobe
Define: Premotor Cortex
integrates movement information with other sensory information inputs to generate perception of stimuli, part of frontal lobe
Define: Primary Auditory Cortex
recieve and process signals from the auditory nerve and integrate them with other sensory inputs, part of the temporal lobe
Define: Occipital Lobe
responsible for vision
Define: Corpus Callosum
nerve fibers that form a pathway between the 2 cerebral hemispheres, allows brain to coordinate full-body movements
Define: Pituitary Gland
regulates other endocrine organs, its function is regulated by the hypothalamus
Define: Pons
function as a relay station for transferring information between the cerebellum and cerebral cortex, also coordinates and controls breathing
Define: Thalamus
recieves sensory input as it travels from the spinal cord and integrates sensory information before sending it to the cortex
Define: Hypothalamus
controls a variety of endocrine functions through release of hormones
Define: Midbrain
main function is to control eye movements, it can also control auditory adn visual motor reflexes
Define: Medulla
has control over involuntary functions
Define: Primary Motor Complex
processes information about the skeletal muscle movement
Define: Primary Somatosensory Cortex
processes feelings of pain, temperature, touch and vibration
Define: Neurons
information transmitting and processing cells of the body, only make up a small part of the brain
Define: Glial cells
make up most of the brain, provide necessary environment for the neurons to function properly, they are the main support cells but also regulate nutrients
Define: Bipolar Neurons
have 2 processes from cell body, specialized neuron
Define: Unipolar Neuron
have one process off cell body, located in peripheral nerves, generally sensory nerves
Define: Multipolar Neurons
contain many branching dendrites, most common in CNS
What are the sequence of events at a chemical synapse?
- presynaptic neurons synthesize neurotransmitters
- action potential depolarizes the membrane and activated voltage gated Ca channels
- synaptic vesicles fuse to the wall of synaptic terminal and release neurotransmitter
- neurotransmitter diffuses across the cleft adn acts on chemical receptors
- receptors cause opening of chemically gated ion channels
- depolarization or hyperpolarization is caused
Define: Spatial Summation of EPSP
additive effect produced by many EPSPs that have been generated at many different synapses on the same postsynaptic neuron at the same time
Define: Temporal Summation of EPSP
additive effect produced by many EPSPs that have been generated at teh same synapse by a series of high-frequency aciton potentials on the presynaptic neuron
Define: Proprioception
the brains awareness to where the limbs are adn teh extent of each muscle contraction
Define: Muscle Spindles
they sense the length and the stretch of the muscle
