Exam 2 Flashcards
How many muscle cells are in motor unit 1?
How many neurons in motor unit 1?
What is the functional classification of the neuron in motor unit 1?
Differentiate b/w gray matter and white matter in structure and function.
3
They conduct action potentials
Grey matter: neural cell bodies
White matter: Milinated neuron fibers axons and dendrites
FUNCTION:
What are the special characteristics of skeletal muscle tissue (e.g. what features enable them to contract under voluntary control)?
- Skeletal muscle cells develop from the fusion of many smaller cells during fetal development, resulting in long, straight muscle fibers that contain many nuclei. Multi-Nucleiated
- When viewed under the microscope, skeletal muscle cells appear to have a striped, or striated, pattern of light and dark regions. These stripes are caused by the regular arrangement of actin and myosin proteins within the cells into structures known as myofibrils.
- Myofibrils are responsible for the skeletal muscles’ great strength and ability to pull with incredible force and propel the body.
- NMJ allows for voluntary control.
What is this component of the nerve?
Neurclemma of shwann cell?
Define Obligodendrocytes
Provide myelination in CNS (white matter)
Wraps arpund portions up to 40 fibers
Consequence: damage increases loose portion of myelination up to 40 fibers
What is the significance of the refractory period?
Nerve is unresponsive to stimulus. No action potentials can take place during the 1-2ms period
Which areas are part of our conscious mind?
Which are unconscious areas of the brain?
Describe examples of how activity in the limbic system may affect autonomic functions.
- Conscious
- Forebrain
- Unconscious
- Midbrain
- Hindbrain
Are the functions of both hemispheres identical?
No
Basic Tasks of the Nervous System….
How is this similar to the normal function of the endocrine system? How is it different? Describe the receptor, control center, and effector in several neural reflexes.
Are the calcium channels in cisternae voltage-gated or chemically-gated?
Voltage
In this flow chart, what do the components in blue have in common?
Explain why the Enteric Nervous System is referred to as the “little brain”.
Where are the Autonomic sensory receptors located?
The blue components all have sensory receptors and neurons
Referred to as little brain because it’s just to digest and make functions work effiently
Plasma membrane of the postsynaptic neuron or effector cell?
Where is CSF made?
Describe the chemical composition of CSF.
How is CSF “recycled”?
- CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles.
- CSF is an ultrafiltrate of plasma, but the exact composition of CSF is altered by active transport. Spinal fluid thus has a much lower concentration of protein, glucose, potassium, calcium and magnesium than does serum.
- CSF is recycled (or absorbed) by special structures in the superior sagittal sinus called arachnoid villi.
- Recycled CSF likely drains back into the ventricles.
Name the two main functions of the spinal cord.
- Connects peripheral nervous system to the brain
- Coordinates simple reflexes such as sending a signal to pull your hand away from a hot object
Describe how a muscle attaches to a bone, as shown in this figure.
- Extracellular connective tissue between muscle fibers find to tendons at distal and proximal ends
- Periosteum binds with tendon at muscles orgin and insertion
How does the Na-K pump contribute to the “potential”?
Why is the cell membrane described as “polarized”?
Because it’s more positive inside and negative outside
What tissue passes through the middle of the third ventricle?
- Running through the third ventricle is the interthalamic adhesion, which contains thalamic neurons and fibers that may connect the two thalami.
- Are oligodendrocytes capable of reproduction?
- Why is this significant?
- No, they do not. The oligodendrocyte precursor cells divide instead and differentiate into oligodendrocytes.
- Significannce
- Thier function is to wrap around axons and provide insultion to increase speed of action potentials down an axon.
- They “stay in place” to offer constant support.
- idk
Name the enzyme that controls these reactions.
Where would you find this enzyme, and why?
What is the blood-brain barrier?
Very tight barriers (tight junctions) destruction of capilaries of brain and spinal cord
Cells are overlaping
Simple squamous epithelium
What are the functions of skeletal muscles?
Is a muscle (e.g. Deltoid) considered a tissue or an organ? Justify your answer.
- Movement
- Structure
- Attached to the bones of the skeletal system are about 700 named skeletal muscles that make up roughly half of a person’s body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves.
Why is there such a large connective tissue component to skeletal muscles?
Elasticity
Extensibility
connect muscle to skeleton
help indiviudal skeletal muscles contract
What is a neuroma?
Tumor found on a shwann cell seath
From which embryonic germ layer do these neuroglia originate?
All neurgolia derive from ectoderm besides microglia
Write the summary equation for aerobic cellular respiration.
C6+H12+6O2——-6CO2+ 6H2O+ATP
Reactants ——————–Products
The appropriate stimulus for skeletal muscle cells is _____________________.
Compare the mode of communication in the nervous and endocrine systems
Nervous: information transmistted as electical impulses (action potentials) by specific neuron cells
Fast acting
Effects are short
Endocrine:Information transmitted by hormone molecules transported by circulitory hormone
Hormone only effect target cell containing hormone receptor
Slow acting
Effect act long-term
Why are there cervical and lumbar enlargements?
- The cervical and lumbar enlargements of the spinal cord result from enlargement of the gray matter that contains the neural machinery necessary to operate the limbs.
Name the two locations where ATP synthesis takes place in a cell.
Mitchondria and cytosal
Why do you think white matter surrounds gray matter in the spinal cord?
If the brain and spinal cord contain no pain receptors, what are the possible explanations for head pain?
- What you feel when you have a headache is not your brain hurting – there are plenty of other areas in your head and neck that do have nociceptors which can perceive pain, and they literally cause the headaches.
What are cisternae and what chemical is stored within the cisternae of muscle cells?
Flattened membrane makes up endoplasmic recticulmum and golgi apparatus
Calcium
The reticular formation extends from the spinal cord to the diencephalon (thalamus).
Name the brain structures in which this neuron “network” is found.
- The reticular formation has projections to the thalamus and cerebral cortex that allow it to exert some control over which sensory signals reach the cerebrum and come to our conscious attention.
- It plays a central role in states of consciousness like alertness and sleep. Injury to the reticular formation can result in irreversible coma.
- Structures
- Traditionally the nuclei are divided into three columns In the median column
- – the raphe nuclei In the medial column
- – gigantocellular nuclei (because of larger size of the cells) In the lateral column
- – parvocellular nuclei (because of smaller size of the cells)
- Thalamus
- Traditionally the nuclei are divided into three columns In the median column
What do the following prefixes mean:
peri-, endo-, epi-, myo-, and sarco-?
peri- around
endo- within ish
epi- on top of ish
myo and mys - muscle,
sarco - flesh
Are dendrites always shorter than axons?
Can the neuron processes that conduct information toward the cell body also be myelinated?
At time 0, does the membrane begin to depolarize or repolarize?
Will a stronger stimulus produce a larger action potential? Explain.
Give an example of where a graded potential would take place.
Depolarize
No because the actin potetial is always the same size
Graded potentials occur in the dendrites and cell body of a neuron
They do not travel down axon
There are 31 segments to the spinal cord; each segment giving rise to a pair of ____________.
The ion channels involved in the propagation of the Action Potential are ______________ -gated.
What information is received by the reticular formation?
How is that information used?
- Some motor neurons send their axons to the reticular formation nuclei, giving rise to the reticulospinal tracts of the spinal cord.
- Maintaining tone, balance, and posture—especially during body movements.
- The reticular formation also relays eye and ear signals to the cerebellum so that the cerebellum can integrate visual, auditory, and vestibular stimuli in motor coordination.
- Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators, which produce rhythmic signals to the muscles of breathing and swallowing.
Differentiate between the absolute refractory period and the relative refractory period.
Absolute refractory: Na channels begin to recover from inactivation
Relative refractory: In need of stronger than normal stimulus to elicit neurnoal excitation
What is the functional unit of contraction in a muscle fiber?
The sacromere is the functional unit. Made up of repeating myofilments of thick filaments ( myosin) and thin fimaments (actin)
The sodium channels on the post-synaptic membrane are _________________________ -gated.
List some of the functions of the cerebrum.
- higher brainfunction such as thought and action.
What molecule serves as the energy source for fermentation?
Glucose is converted to 2 pyruvates
Give one location where these neurons would be found in the body?
Name the important nuclei (control centers) in the pons and medulla.
- Pons
- Pheutotaxic Area
- Respiratory ‘speed’
- Apneustic Area
- inspiration by stimilation of the neruons in the medulla with constant stimulus
- Pheutotaxic Area
- Medulla
- The Cardiovascular Center
- Obvious
- Reflex Center
- Reflex centers of vomiting, coughing, sneezing, and swallowing. These reflexes which include the pharyngeal reflex, the swallowing reflex.
- Vasomotor Center
- Has baroreceptors that sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained,
- Ventilation Center
- The control of ventilation via signals from the carotid and aortic bodies.
- The Cardiovascular Center
What cells myelinate fibers in the PNS?
Shwann Cells
Can cells store ATP?
Can cells store CrP?
No- glucose stored as glycogen in cells
Yes. Muscle cells can store CrP
Label the nerves in these figures.
DOM ATTACH IMAGE
Define Microglia
- Small mobile cells that are similar to macrophage
- Enter during embryonic development and stay there
- Consider a tissure because: 1. not circulating 2. not migrating
- Microglia become protective phagsitize cells
What is this and what are the arrows pointing to?
What kinds of information are sent to the cerebellum, and how is this related to its function?
- It receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine-tune motor activity.
- IT REFINES MOTOR MOVEMENTS
In addition to the presence of a myelin sheath, what else may increase the speed of conduction along a neuron process (axon or dendrite)?
Saltatory conduction? The action potentials jump from node to node withough depolarizing the rgion under the myelin sheath
-Helps to prevent short circiting
Compare the possible functions of these neuron types.
- Multi polar
- bi polar
- uni polar
Multi-polar: 1 axon, multiple dendrites, motor neruron, mylenated axon, contains interneurons
Function: great amount of information from other neurons through integration
Function: action potential into CNS
Bi-polar: sensory for transmission of special senses
Unipolar: Sensory, cell body located in dorsal root ganglion
Function: Distal portions of peripheral process acts as receptive endings. The rest act as axon w/ central process
What is a myofibril, actin, and myosin?
Myofibril: group of repeating actin and mysoin
Actin: Protien formed with myosin. Involved in motion of the other cells
Myosin: Movement
What are the three types of muscle tissue?
From which embryonic germ layer are they derived?
Smooth, Cardiac, and Skeletal
THE MESODERM
Types Energy Metabolism in Muscle Cells
- The phosphagen system
- Aerobic cellular respiration
- Fermentation (anaerobic metabolism)
Which cranial nerves are classified as sensory?…motor?…mixed?
Senosory:
Olfactory
Optic
Vestibuloconchliar
Motor:
Oculomotor
Trochlear
Aducens
Accessory
Hypoglossal
Both:
Trigeminal
Facial
Glossopharyngeal
Vagus
Why is there such a large c.t. component to nerves?
Where does the muscle cell get these molecules?
Define Astrocytes
- Control blood flow to area in brain
- Movement of neutrients and watse between neurons and blood because blood brain barrier
- Control neurotransmitter availabilty
- Capable of mitosis in brain to create scar tissue
- Protects and supports
What substrate(s) are available for aerobic energy metabolism? … for anaerobicmetabolism?
Besides Ca+2, what must also be present in order for myosin to bind to actin?
What is the function of the dural sinuses?
- The dural sinusesare venous channels found between the periosteal and meningeal layers of dura mater in the brain.
- They receive blood from internal and external veins of the brain, receive cerebrospinal fluid (CSF) from the subarachnoid space via arachnoid granulations, and mainly empty into the internal jugular vein.
Why is the refractory period important in neurons?
Na ion channels are inacivated at this time. When another stimulus is given to neuron NO MATTER how strong
WILL NOT produce another action potential
Takes about 1-2ms
Which neuroglia have a protective function?
Which neuroglia provide myelination in the CNS?
Which neuroglia are involved in transport?
Name the cell type that provides myelination in the PNS.
How are oligodendrocytes and Schwann cells different?
Oligodendrocytes provides white matter
Astrocytes
The appropriate term to describe an axon branch (as shown in these figures) is ___________________.
Axon coladeral- wraps around but doesn’t touch the sarcolema
Branching releases neurotransimitters- acetyocholine (short time contraction)
Once acetyocholine is released -Cholinesterase distroys it causing the enzyme to be broken into astite and choline so it can be reabsorbed
What are is Basic Structure of a Reflex Arc?
Sensory receptor is triggered. -Ditect change
Sensory neuron released and passes through the dorsal area of the spinal cord
Synapses with the motor neuron that passes through the ventral horn of of spinal cord
Sent to the effector to create homeostasis
Interneuron: communication allows you to conscinsouly know about. Also creates faster communication
Why is the refractory period important in muscle cells?
Are nerves considered organs of the nervous system?
No nerves are cells
Is the release of neurotransmitter active transport or passive transport?
Is the influx of Na+ ions by active transport or passive transport?
How does the influx of Na+ ions change the transmembrane electrochemical potential?
Active
Active
Makes it more - inside the cell causing it to depolorize
What differences between gray matter and white matter?
Grey: Neruon cell bodies
White: milinated neuron fibers, axons, and dendrites.
What structures are found predominately in gray matter?
…in white matter?
Grey: Neuron cell bodies
White: Milinated neuron fibers, axons, and dendrites
Connects cerebral hemispheres
How does the graded potential differ between an excitatory synapse and an inhibitory one?
- Is there a neurolemmal sheath around myelinated fibers in the CNS?
- Why is this significant?
- Nah,
- Neurolemma serves a protective function for peripheral nerve fibers.
- This is not needed in the CNS because of the BBB.
Sensory Input:________
Integration:___________
Motor output:_________
Sensory Input: Receptors monitor both external and internal environments.
Integration: Process the information (at synapses) and often integrate it with stored information.
Motor output: If necessary, signal effector organs to make an appropriate response.
What are the benefits of aerobic cell metabolism?
Convert fats, protiens, and carbs—–energy
Continues indefinetly
Efficient
Free burning
The calcium channels on the synaptic terminal are __________________________ -gated.
voltage
Define Milination:
Function of neurgolia which provides insulation by adding membrane of neurgolia.
Wraps around axons and dendrites that travel up and down the spinal cord
Each t-tubule is an extension of the ________________.
Sarcolemma
How is a chemical message converted into an electical message?
List and briefly describe the types of functional areas.
Sensory areas
- •Primary Sensory Cortex – makes you aware of a sensation
- •Association areas – give meaning to/make associations with a sensation
- •Multimodal Association Areas – make associations between different types of stimuli
Motor areas – allow you to act upon a sensation
- •Premotor Cortex – plans movements; then
- •Primary Motor Cortex – sends signals to generate movements
- •2 special motor cortices (Frontal Eye Field, Broca’s area)
Are the calcium channels in cisternae voltage-gated or chemically-gated?
Besides Ca+2, what must also be present in order for myosin to bind to actin?
Which steps require ATP?
Voltage
Once myosin is connected to actin ADP is released and in order for myosin to release from actin ATP is required
ATP binds to myosin head to detach from actin
Once ATP is broken down to ADP+P the myosin head extends
This sequence keeps repeating
How is myelination different in the CNS from the PNS?
- CNS
- myelination from oligodendrcites
- A single oligodendrocyte can extend its processes to 50 axons, wrapping approximately 1 μm of myelin sheath around each axon
- PNS
- myelination from Schwann Cells
- Schwann cells can wrap around only one axon.
Regeneration of Peripheral Nerve Fibers
How might this injury occur? Is this a sensory neuron, interneuron, or motor neuron? (What function would be lost?)
Where does awareness of sensation occur, and how is this different from sensation, and perception?
Sensation: physical stimulus registered by sensory organs
Perception: The way we interpret the sensations
This figure demonstrates a polysynaptic pain reflex arc.
Draw the monosynaptic muscle stretch reflex arc.
Spinal reflex to protect body from damaging stimuli. Motor, sensory, and interneuron
Stretch reflex: muscle contraction
provides automuc regulation of skeltal muscle length
muscle lengthens– spindle stetched–nerve activity increases
Stretch reflex: has only 2 neurons: motor and sensory
The specialization of the sarcolemma that contains receptors for acetylcholine (ACH) is called ___________________.
Folding of the sarcolema = motor end plate
Define Ependyma
like a lining of epythelial cells with cilia
Lines cavities within brain, central canal of spinal cord, and ventricals in brain
Cilia- helps circulate throughout CNS
Why is the resting potential a negative number?
The resting potential is about -70mV which means that it’s 70 mV less than the outside
More Na outside and more K inside
What is the function of CSF?
- It acts as a cushion or buffer for the brain’s cortex, providing basic mechanical and immunological protection to the brain inside the skull.
Describe the structure and function of connective tissue components in skeletal muscles.
- Fassicles
- Division of columns of a muscle
- Periysium
- connective tissue that surrounds fassicles
- Epinysium
- fibriuos connective tissue from the tendons that extends around skeletal muscle
Define a motor unit and describe the function of the neuromuscular (myoneural) junction.
- Motor Unit
- functional unit of movement made of
- neuron
- skeletal muscle
- functional unit of movement made of
- Function of NMJ
- transmits signals from neuron to muscle fiber for muscle contraction
- quick
- reliable
Distinguish between the responses called all-or-none (Action Potentials) and graded (End-plate Potentials) following neuronal stimulation at the motor end-plate.
- Action Potentials
- depolarization of membrane
- all or nothing
- Graded potentials
- are changes in membrane potential that vary in size
- chemical or mechanical gated
Briefly describe the sequence of chemical and physical events which lead to muscle contraction and relaxation
- Motor Neuron
- releases acetyalcholine
- Acetylcholine binds to receptor on muscle fiber, causing calcium influx
