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