Phys 335 UW Madison Exam 1

Whforebrainat does the

The cerebrum and the diencephalon (thalamus, hypothalamus, epithalamus)

Dynamic Constancy

When a given variable, such as blood glucose, may vary in the short term but is stable and predictable when averaged over the long term.

How does a steady state and equilibrium differ?

A steady state requires an input of energy to maintain a constant condition. Equilibrium can maintain a constant condition without the input of energy.

feedforward process

Changes in regulatory variables are anticipated and prepared for before they actually occur.

Ex- control of body temperature

What is the defining feature that differentiates a prokaryote from a eukaryote?

A eukaryote has a plasma membrane surrounding the cell's nucleus.

integral membrane proteins

They are closely associated with the membrane lipids and cannot be extracted from the membrane without disrupting the lipid bilayer. They are amphipathic.

peripheral membrane proteins

They are not amphipathic and do not associate with the non polar regions of the lipids in the interior of the membrane. They are located at the membrane surface where they are bound to the polar regions of the integral membrane proteins.

desmosomes

Characterized by accumulations of proteins known as "dense plaques" along the cytoplasmic surface of the plasma membrane.

cadherins

Proteins that extend from the cell into the extracellular space where they link up and bind with cadherins from and adjacent cell.

tight junction

It forms when the extracellular surfaces of two adjacent plasma membranes join together so that no extracellular space remains between them. Occurs in a band around the entire circumference of a cell.

gap junctions

They consist of protein channels linking the cytosol of adjacent cells.

ribosome

It is the protein factory of a cell.

rough ER

It is involved in packaging proteins

smooth ER

The site of some lipid molecule synthesis, it participates in detoxification of certain hydrophobic molecules, and it stores and releases Ca2+ involved in controlling various cell activities.

Golgi Apparatus

The golgi modifies and sorts proteins into transport vesicles that will travel to various cell organelles or to the plasma membrane.

lysosome

The garbage man of the cell. Breaks down damaged cell organelles and bacteria and other debris.

simple diffusion

The movement of molecules from one location to another solely as a result of their random thermal motion.

net flux

The difference between two compartments at any instant.

factors that determine the magnitude of net flux

Temperature, mass of molecule, surface area, and the medium through which molecules are moving.

Fick's first law of diffusion

J = PA (Co + Ci)

where J = magnitude of net flux/rate of diffusion

Co = [outside] Ci = [inside]

A = surface area of the membrane

P = membrane permeability coefficient

membrane potential

The magnitude which is measured in millivolts. Provides an electrical force that influences the movement of ions across the membrane.

channel gating

The process of opening and closing ion channels.

How does active transport differ from facilitated diffusion?

Active transport uses energy to move a substance uphill across a membrane (against its concentration gradient).

Na+/K+ -ATPase Pump

This transporter moves Na+ from intracellular to extracellular fluid and K+ in the opposite direction in a 3:2 ratio. This is a primary active transporter.

concentration of Na+ and K+ both intracellularly and extracellularly

Intracellular- Na+ is 15 mM and K+ is 150 mM

Extracellular- Na+ is 145 mM and K+ is 5 mM

aquaporins

Membrane proteins that form channels through which water can diffuse.

Osmosis

What is the net diffusion of water across a membrane known as?

semipermeable membrane

A membrane that is permeable to water but not solutes.

osmotic pressure

The pressure that must be applied to the solution to prevent net flow of water into it.

isotonic solution

A solution that contains 300 mOsmol/L of non-penetrating solutes. Does not cause a change in cell volume.

hypertonic solution

A solution that contains >300 mOsmol/L of non-penetrating solutes. Causes cells to shrink

hypotonic solution

A solution that contains <300 mOsmol/L of non-penetrating solutes. Causes cells to swell.

isoosmotic solution

A solution that contains 300 mOsmol/L of solute regardless of its composition of membrane-penetrating and non-penetrating solutes.

hyperosmotic solution

A solution that contains >300mOsmol/L of solute regardless of its composition of membrane-penetrating and non-penetrating solutes.

hypoosmotic solution

A solution that contains <300 mOsmol/L of solute regardless of its composition of membrane-penetrating and non-penetrating solutes.

peripheral nervous system (PNS)

Nerves that connect the brain and spinal cord with the body's muscles, glands, sense organs, and other tissues.

A neuron

What is the functional unit of the nervous system?

dendrite

A series of highly branched outgrowths of the cell that receive incoming information from other neurons.

axon

A long process that extends from the cell body and carries outgoing signals to its target cells.

axon hillock

The region of the axon that arises from the cell body. Location where propagated electrical signals are generated.

axon terminal

This is responsible for releasing neurotransmitters from the axon.

Varicosites

Bulging areas along the axon where some neurons release their chemical messengers from are called what?

oligodendrocytes in the CNS

Schwann cells in the PNS

In the brain and spinal cord, what type of glial cells forms myelin? What are these called in the PNS?

What is the difference between anterograde and retrograde?

Anterograde is transport from the cell body toward the axon terminal (Kinesins)

Retrograde is transport is in the opposite direction (dyneins)

afferent neurons

They convey information from the tissues and organs of the body toward the CNS.

efferent neurons

They convey information away from the CNS to effector cells like muscle, gland, or other cells.

interneurons

They connect neurons within the CNS

fraction of efferent/afferent/interneurons

For every afferent neuron that enters the CNS, there are roughly 10 efferent neurons and 200,000 interneurons.

nerve

A bundle of axons (fibers) bound together by connective tissue.

interneurons

In the CNS

Where do most synapses occur?

Between an axon terminal of one neuron and a dendrite or the cell body of a second neuron.

astrocyte

A type of CNS glial cell that helps regulate the composition of the extracellular fluid in the CNS by removing K+ ions and neurotransmitters around synapses. Also, they stimulate the formation of tight junctions between the cells that make up walls of capillaries found in the CNS.

ependymal cells

To line the fluid-filled cavities within the brain and spinal cord and regulate the production and flow of cerebrospinal fluid.

plasticity

Our brain's ability to modify its structure and function in response to stimulation or injury throughout the lifespan.

Ohm's Law

The effect of voltage (V) and resistance (R) on current (I)

I = V/R

resting membrane potential

At rest, neurons have a potential difference across their plasma membranes, with the inside of the cell negatively charged with respect to the outside.

Nernst equation

It describes the equilibrium potential for any ion.

E(ion) = 61/z log (Cout/Cin) where

C=[in/out]

Z= valence of the ion

61 = a constant

graded potentials

Changes in membrane potential that are confined to a relatively small region of the plasma membrane. Their magnitude can vary.

Voltage-gated ion channels

What type of ion channels give a membrane the ability to undergo action potentials?

absolute refractory period

The period when voltage-gated Na+ channels are either already open or have proceeded to the inactivated state during the first action potential.

relative refractory period

A period when some, but not all, voltage-gated Na+ channels have returned to a resting state. It is possible for a new stimulus to depolarize the membrane above the threshold potential but only if the stimulus is large in magnitude or outlasts the relative refractory period.

What is the difference between and excitatory and inhibitory synapse?

An excitatory synapse is where the membrane potential of a postsynaptic neuron is depolarized (Brought closer towards threshold) while an inhibitory synapse is where it is hyperpolarized.

What is the difference between ionotropic receptors and metabotropic receptors?

Ionotropic receptors are ion channels while metabotropic receptors indirectly influence ion channels through a G protein and/or a second messenger.

temporal summation

When input signals arrive from the same presynaptic cell at different times.

spatial summation

When 2 inputs occur at different locations on the cell.

agonists

Ligands that bind to a receptor and produce a response similar to the normal activation of said receptor.

antagonists

Ligands that bind to the receptor but are unable to activate it. They prevent binding of the normal neurotransmitters at the synapse.

False. A group of axons running together in the CNS is called a pathway, tract, or commissure when it links the right and left halves of the brain

T/F: There are nerves in the CNS

hindbrain

The pons, medulla oblongata, and cerebellum

brainstem

The pons, midbrain, and medulla oblongata

cerebral cortex

Grey and white matter.

white matter

Myelinated fiber tracts.

grey matter

Cell bodies

corpus callosum

A massive bundle of nerve fibers that connect the left and right cerebral hemispheres.

gyri (gyrus)

What are the ridges of the brain called?

Sulci (sulcus)

What are the grooves of the brain called?

What parts of the brain are associated with the limbic system?

Portions of the frontal-lobe cortex, temporal lobe, thalamus, and hypothalamus

thalamus

A synaptic relay station and important integrating center for most inputs to the cortex. Key function is general arousal. Also involved in focusing attention.

hypothalamus

The single most important control area for homeostatic regulation of the internal environment (eating and drinking)

pituitary gland

Regulated by the hypothalamus. An important endocrine structure.

pineal gland

Regulation of circadian rhythm through the release of the hormone melatonin

cerebellum

Coordinating movements and controlling posture and balance.

reticular formation

It is the one part of the brain absolutely necessary for life. It receives and integrates input from all regions of the CNS and processes a great deal of neuronal information.

Afferent neurons via the dorsal root

What neurons enter through the dorsal horns?

Efferent neurons via the ventral root

What neurons leave the spinal cord through the ventral horns?

True

T/F: The dorsal root and ventral root of a particular level will combine to form a spinal nerve

43:

12 cranial nerve sets

31 spinal nerve sets

How many pairs of nerves does the PNS have?

Cervical- 8

Thoracic- 12

Lumbar- 5

Sacral- 5

coccygeal- 1

How many pairs of neurons leave each segment of the spinal cord?

True:

afferent = optic nerve

efferent = hypoglossal nerve

T/F: spinal nerves can carry either afferent or efferent neurons, whereas some of the cranial nerves can only carry one or the other.

False, they are part of the efferent division of the PNS

T/F: The somatic and autonomic nervous systems are part of the afferent division of the PNS.

The somatic nervous system innervates skeletal muscle while the autonomic nervous system innervates smooth and cardiac muscle, glands, neurons in the GI tract, and other tissues.

What is the difference between the somatic nervous system and the autonomic nervous system?

Contraction of skeletal muscle cells

What does excitation of motor neurons lead to?

autonomic ganglion

The cell cluster where a synapse between 2 neurons that is outside the CNS.

dual innervation

Where a part of the body is innervated by both sympathetic and parasympathetic fibers.

The sympathetic system.

This refers to the fact that heart rate and blood pressure increase and pupils dilate amongst other effects.

Which system operates under the "fight or flight" response? What does this mean?

The parasympathetic system. Opposite effects of the sympathetic response, or just a complete lack of those responses.

What system operates under the "rest and digest" response?

True. There tends to be an interplay between the two systems.

T/F: The two divisions of the autonomic nervous system (sympathetic and parasympathetic) hardly ever operate independently.

The choroid plexus. Completes this at a rate that replenishes fluid 3x a day.

What produces CSF?

perception

A person's awareness of a sensation.

adaptation

A decrease in receptor sensitivity which results in a decrease in action potential frequency in an afferent neuron despite the continuous presence of a stimulus.