Animal Science 214 Exam 2
Ganglia
Peripheral Nervous System
Saltatory Conduction
"Jumping" of an action potential from node to node along an axon
What is the most distinguishing characteristic of muscle tissue?
The ability to transform chemical energy into mechanical energy to move the body
You discover that a new chemical compound interacts with K+ voltage-dependent channels. What would be the effect on a neuron if the chemical came into contact with the axonal membrane?
The neuron would be unable to repolarize
What form of communication is the Nervous System?
The second form of communication
Ion
Voltage gated channels (Na)
What are the types of action?
-Voltage gated channels (ions, electrical channels) -Chemical gated channels (through neurotransmitters) -Mechanically gated channels
What are the refractory periods?
-Absolute refractory period: no more action potential can fire -Relative refractory period: another action potential has the potential to fire
Which of the following is NOT part of the intrinsic conduction system of the heart? -Sinoatrial (SA) node -Atrioventricular (AV) valve -Bundle branches -Atrioventricular (AV) node
-Atrioventricular (AV) valve
What are the properties of neurons?
-Excitable (ability to change according to external stimuli) -Conductivity -Secretion
Action Potential Characteristics
-Generated at axon hillock -All or none -Threshold must be met
Depolarization Characteristics
-High Sodium influx -Makes cell more positive
What are nerve impulses?
-IPSP (Inhibitory) -EPSP (Excitatory)
What are the types of nerve cells?
-Neurons (carry electrical signals) -Neuroglial (support nerve cells and provide nutrients to them)
Repolarization Characteristics
-Potassium leaves the cell -Makes cell more negative
What are muscle functions?
-Produce movement -Maintain posture and body position -Stabilize joints -Generates heat
What are the characteristics of muscle?
-Responsive (to chemical signals, stretch, electrical signals) -Conductivity -Contracting -Extensibility -Elasticity
What is the role of sodium-potassium pump?
-Restore resting electrical conditions -Rebalances ion concentration of cell
Hyperpolarization Characteristics
-Since Potassium is a slow moving ion, cells continue to become more negative -Cells become hyperpolarized (super negative)
What are the three muscle types and which are striated?
-Skeletal (longest, striated, voluntary) -Cardiac (In the walls of the heart, striated) -Smooth (In hollow organs, no striations)
What are the 2 divisions of the nervous system?
1. Central Nervous System (Brain and Spinal cord) 2. Peripheral Nervous System (Cranial nerves, spinal nerves, and ganglia)
What happens with neuromuscular junctions?
1. Stimulus generates 2. Action Potential generates
What are the 3 basic steps of the nervous system?
1. sense organs (receive information) 2. brain and spinal cord (determine responses) 3. brain and spinal cord (issue commands) to glands and muscles
Myelination
80% fat or lipid, 20% protein
What make up myofibrils?
A bands, H bands, and I bands
What's action potential also called?
A nerve impulse transmitted by axons
A Bands
Action and Myosin
What mechanisms is most significant in returning Na+ and K+ concentrations to resting ionic conditions?
Active transport by the Na+-K+ pump
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?
Acetylcholinesterase destroying the ACh
I Bands
Actin (thin)
The sliding filament model of contraction involves ___________
Actin and myosin sliding past each other and partially overlapping
What happens when the threshold is reached?
Action Potential
What can graded potentials have?
Amplitudes of various sizes
What is relative refractory period?
An exceptionally strong stimulus can trigger a response
What are the types of neuroglial cells?
Astrocytes, microglial, ependymal, oligodendrocytes, and satellite
What are the 3 ways neurons can interact?
Axodentritic synapse, axosomatic synapse, and axoaxonic synapse
Where does action potential happen at?
Axon hilicate (triangle)
A person who lacks agglutinogen A but has agglutinogen B would have blood type __________.
B
Why won't a neuron respond to a 2nd stimulus equal strength to the first?
Because the neuron is an absolute refractory period
What is depolarization?
Becoming less negative and more positive
What is repolarization?
Becoming more negative
What is acetylocholinesterase?
Breaks down acetylcholine (ase=enzymes breakdown)
Which is not involved in the transfer of info across a chemical synapse? A. Neurotransmitter is released B. Neurotransmitter binds to receptors C. Direct flow of ions from a neuron to the next D. Calcium channels open
C. Direct flow of ions from a neuron to the next
What does repolarization in cardiac muscles result in?
Calcium leaving the cell
Nuclei
Central Nervous System
What are the types of synapses?
Chemical and Electrical/Gap Junction
Neurotransmitter
Chemical messenger from the brain
Axon
Conduct electrical impulses away from the cell
What do the symptoms of curare poisoning look like?
Curare will only affect muscles with ACh receptors, paralyzing them
Why are gap junctions a vital part of the intercellular connection of cardiac muscles?
Gap junctions allow action potentials to spread to connected cells
The _____ cells are found in the CNS, while the _____ cells are find in the PNS; both wrap around nerve fibers
Oligodendrocytes, Schwann
What is the difference between epimyosin and perimyosin?
Epimyosin: All of it Perimyosin: Little bundles
What is an entire muscle surrounded by?
Epimysium
T or F, osmotic pressure is created by the presence in a fluid of small diffusible molecules that easily move through the capillary membrane
False
T or F, the role of the chordae tendineae is to open the AV valves at the appropriate time
False
Addition of more mitochondria to a muscle fiber will have the least effect on ________
Fast glycolytic fibers
The kidneys filter the blood; it is necessary for plasma, both fluid and dissolved chemicals, to be rapidly removed from the blood without the removal of larger proteins or cells. Which capillary would be best suited for this filtration?
Fenestrated capillaries
What is synapses?
Functional connection between a neuron and another cell
Perimysium
One bundle
What defines integration?
Interpretation of sensory input and determining what should be done
Choose the statement that is true concerning hemoglobin -It is found in the plasma portion of blood -It can bind a maximum of three oxygen molecules -When hemoglobin is not bound to oxygen, it appears blue -It is composed of four protein chains and four heme groups
It is composed of four protein chains and four heme groups
What happens if ATP is depleted?
It wouldn't work; It'd be contracted because of the inability to break
Blood within the pulmonary veins returns to the _________
Left atrium
What heart chamber receives blood from the pulmonary veins?
Left atrium
What chamber pumps oxygenated blood out the aorta to the systemic circuit?
Left ventricle
What pressure is responsible for reabsorption and for pulling fluids into the venous end of capillaries?
Osmotic pressure in capillary (OPc)
Propagation of an Action Potential
Local currents affect the adjacent areas (propagates signal forward)
What describes RMP?
Most Na and K are closed
What part of the sarcolemma contains acetylcholine receptors?
Motor end plate
A sarcomere is part of a...
Myofibril (muscle fiber)
H Bands
Myosin (thick filament)
What are examples of ions?
Na+. K+, Ca+
What happens across a synapse?
Neurotransmitters release and bind and then Ca+ opens
Schwann cells are functionally similar to __________
Oligodendrocytes
Dendrites
Receive and transmit electrical impulses
What phase of Action Potential, are voltage gated K channels open and Na are closed?
Repolarization
What would lead to a decrease in heart rate?
Rest and Digest, Palasamethic
What chamber receives blood from the superior and inferior vena cavae?
Right atrium
What heart chamber pumps unoxygenated blood out the pulmonary trunk?
Right ventricle
The order of impluse conduction in the heart, from beginning to end, is _________
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers
Myofibrils are composed of repeating contractice units called?
Sarcomeres
What structure in skeletal muscle cells functions in calcium storage?
Sarcoplasmic reticulum
Muscle tissues have all of the following properties except _________. -Secretion -Excitability -Contractibility -Extensibility
Secretion
What are the 3 steps of the nervous system?
Sensory Input, Integration, Motor Output
What are the fundamental types of neurons?
Sensory neurons, inter neurons, and motor neurons
The sensory or afferent division of the PNS transmits information from the _____ to the CNS
Skin
Creatine phosphate functions in the muscle cell by _______
Storing energy that will be transferred to ADP to resynthesize ATP
What are grade potentials?
Strength determined by the amount of neurotransmitter release and time
What is polarization?
The state of being negative
Epimysium
The whole muscle (covers all of it)
Which of the following statements is not true of the precapillary sphincters? -They decrease the osmotic pressure in the thoroughfare channel -They increase or decrease rates of perfusion to the tissues served by the true capillaries -They regulate the flow of blood to tissues served by the true capillaries -They allow blood to bypass the true capillaries that are fed by the metarteriole
They decrease the osmotic pressure in the thoroughfare channel
Describe cardiac contractions
They're stimulated electronically, are spontaneous, rhythmic, and can cause depolarization in the rest of the heart
How do neurons signal?
Through Action Potential
What happens when cardiac cells stimulate?
Triggers the ion, calcium to leave the cell
T or F, if the neuron membrane becomes more permeable to Na+, Na+ will transport across the membrane, causing the cell to depolarize
True
T or F, the force of muscle contraction is controlled by multiple motor unit summation or recruitment
True
The heart is actually (one, two, or three) pumps?
Two pumps
What are the 3 structural classes of neurons?
Unipolar, bipolar, and multipolar
What channels do K and Na have?
Voltage gated channels
What describes the resting state?
When all Na and K are closed
What's autonacity?
When cardiac contractions cause depolarization in the rest of the heart
When will a neuron not respond?
When it's in absolute refractory period
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of _______
capillaries
What is hyperpolarization?
goes past -70 and becomes extremely negative
Why does rigor mortis occur?
no ATP is available to release attached actin and myosin molecules
In red bone marrow newly formed blood cells enter the circulation. You would expect to see many ________ type of capillaries in red bone marrow.
sinusoid capillaries
If a post synaptic neuron is stimulated to threshold by spatial summation this implies that _______
the postsynaptic cells has many synapses with many presynaptic neurons
