BSC2085 Lecture Exam 3

What makes up the Central Nervous System?

brain and spinal cord

What makes up the Peripheral Nervous System?

cranial and spinal nerves

What are the two divisions of the Peripheral Nervous System?

1. Somatic
2. Visceral (autonomic)

Somatic Nervous System

-Signals from skin, muscles, joints
-Response to skeletal muscles

Visceral Nervous System

-Signals from viscera (internal organs)
-Response to cardiac muscle, smooth muscles and glands

Somatic vs Autonomic Nervous System (Effector Organ)

Somatic: Skeletal muscles
Autonomic: Cardiac muscles, smooth muscle, and gland secretion

Somatic vs Autonomic Nervous System (Control)

Somatic: Voluntary
Autonomic: Involuntary

Somatic vs Autonomic Nervous System (Neurotransmitter)

Somatic: Acetylcholine
Autonomic: Acetylcholine (ACh) and norepinephrine (NE)

Somatic vs Autonomic Nervous System (Effect)

Somatic: Always excitatory. Results in muscle contraction
Autonomic: Excitatory or Inhibitory

Somatic vs Autonomic Nervous System (Efferent Pathway)

Somatic: 1 neuron from CNS to muscle
Autonomic: 2 neurons that synapse in ganglion

Somatic vs Autonomic Nervous Systems

Somatic: One neuron, ACh
Autonomic: Two neurons, preganglionic and postganglionic neurons, ACh or NE

What two divisions make up the Autonomic Nervous System?

1. Sympathetic
2. Parasympathetic

Sympathetic vs Parasympathetic Division of Autonomic NS (Location)

Sympathetic: Thoraco-lumbar
Parasympathetic: Cranio-Sacral

Sympathetic vs Parasympathetic Division of Autonomic NS (Neuron Length)

Sympathetic:
-Ganglia are near the spinal cord.
-Short preganglionic
-long postganglionic

Parasympathetic:
-Ganglia are near the effector organ
-Long preganglionic
-Short postganglionic

Sympathetic vs Parasympathetic Division of Autonomic NS (Effect)

Sympathetic: Usually causes excitation
Parasympathetic: Usually causes inhibition

Sympathetic vs Parasympathetic Division of Autonomic NS (Functions)

Sympathetic: Fight or Flight
Parasympathetic: Rest and Digest

Sympathetic vs Parasympathetic Division of Autonomic NS (Postganglionic Neurotransmitter)

Sympathetic: Epinephrine and norepinephrine or Acetylcholine (ACh)
Parasympathetic: Acetycholine (ACh)

Sympathetic Division of Autonomic Nervous System

-Neurons from the lateral horn of the spinal cord (preganglionic neurons) project to ganglia on either side of the vertebral column

-Axons from the ganglionic neurons (postganglionic fibers) then travel to target organs throughout the body

Parasympathetic Division of Autonomic Nervous System

-Neurons from the brainstem or lateral horn of the sacral spinal cord, project to ganglia near or within various organs of the body

-Axons from these ganglionic neurons then travel a short distance to these target organs

Effects of ANS on certain Organs: The Heart

Sympathetic: Increases heart rate and blood pressure
Parasympathetic: Decreases heart rate and blood pressure

Effects of ANS on certain Organs: Digestion

Sympathetic: Inhibit
Parasympathetic: Stimulate

Effects of ANS on certain Organs: Bladder Muscle and Internal Urethral Sphincter

Sympathetic: Inhibits micturition- Relaxes muscles and keeps urethral sphincter closed

Parasympathetic: Allows micturition- Contracts muscle opens urethral sphincter

Effects of ANS on certain Organs: Lung Bronchioles

Sympathetic: Dilation
Parasympathetic: Constriction

Sympathetic System Effect on Blood Vessels

1. Vasodilation
2. Vasoconstriction

Vasodilation

Widening of blood vessels to increase blood flow to the brain, skeletal and cardiac muscles

Vasoconstriction

narrowing of blood vessels to the digestive system and the skin

What cells of the nervous system transmit signals?

neurons

What cells of the nervous system provide a support system for the neurons?

neuroglia

What part of a nerve cell accepts signals from other neurons?

Dendrites

Where in a nerve cell are impulses (action potentials) generated?

Axon hillock: nerve impulses (action potential) is generated in the trigger zone

What type of Neuroglia cell secretes and circulates CSF?

Ependymal Cell:
-Lines the brain cavity
-Secretes and circulates CSF

What type of Neuroglia cell supports and nourishes neurons in the CNS?

Astrocytes:
-Supports and nourishes neurons
-Forms blood brain barrier

What type of Neuroglia cell forms the myelin sheath around neurons in the CNS?

Oligodendrocytes

What type of Neuroglia cell forms myelin around neurons in the PNS?

Schwann Cells

What type of Neuroglia cell surround the soma (cell body of neurons) in the ganglia that aids in protection and electrical insulation in the PNS?

Satellite Cells

What is the area of an axon that are not covered with myelin called?

Nodes of Ranvier

Areas of the brain & spinal cord occupied by dense collections of myelinated axons are called?

White matter

Areas of the brain & spinal cord containing cell bodies, dendrites, neuroglia, and unmyelinated axons are called?

Gray Matter

Neurons that detect sensory stimuli and conduct them to the CNS are called?

Sensory / Afferent neurons

Neurons that connect incoming sensory input with outgoing motor response are called?

Interneurons

Neurons that send motor responses away from the CNS are called?

Motor / Efferent Neurons

What is the Resting Potential voltage within a cell membrane?

-70 mV

How is the membrane defined?

It is Polarized; Inside the membrane is more negatively charged

The Sodium Potassium Pump is able to maintain a resting potential by the exchange of what and how many ions?

The Na-K ATPase pump sends out 3 Na+ ions in exchange for 2 K+ ions in, maintaining a stable resting membrane potential of -70 mV

When a cell membrane is resting, what is open that allows movement of ions in and out of the cell membrane?

Leakage Ion Channels.
-The membrane is more permeable to K+ than Na+, so there is more K+ leaking out.

Potentials that are short range, have a temporary change in membrane voltage are called what?

Graded Potentials

Where do graded potentials occur?

They occur at the dendrites

Stronger stimulus, opening more Na+ channels results in what?

Action Potential

What voltage must be reached in order to initiate an action potential?

-55 mV
Local potentials must change voltage to -55mV, which is called the threshold Potential. Only then can action potential start.

Small Molecules made by the body that allow neurons to communicate and talk with each other are called what?

Neurotransmitters

What structures carry neurotransmitters through to the pre-synapse, eventually releasing them through the membrane?

Synaptic vesicles

What ion allows the vesicles to bind with the membrane and allow the neurotransmitters to be released into the synaptic cleft?

Calcium ions

What 3 layers form the meninges of the spinal cord?

1. Dura Mater
2. Arachnoid Mater
3. Pia Mater

What space within the meninges contains fat?

The Epidural Space

What space within the meninges contains CSF?

The Subarachnoid Space

Dorsal Roots emerging from the spinal cord carry what type of neurons?

Sensory (Afferent) Neurons

Ventral Roots emerging from the spinal cord carry what type of neurons?

Motor (Efferent) Neurons

A bundle of neuronal axons that are all located in a specific area of the spinal cord and travel to the same place are called?

A Tract

How many spinal nerves are there in the Cervical , Thoracic, Lumbar, Sacral, Coccygeal regions

1. Cervical: 8
2. Thoracic: 12
3. Lumbar: 5
4. Sacral: 5
5. Coccygeal: 1

Nerve fibers gathered in bundles are called what?

fascicles

Two examples of intersecting branches of nerves are called....?

Nerve Plexus:
-Brachial plexus
-Sacral plexus

A motor response to stimuli that are quick, involuntary and normally occur in the same way each time are called what?

A Reflex

What type of neuron does the path of a reflex travel through passing from the dorsal root/posterior gray horn to the anterior gray horn/ventral root of the spinal cord?

Stimulus
→ Somatic sensory receptor in skin, muscles, or tendons
→ Sensory afferent neuron
→ Dorsal root ganglion
→ Dorsal root of spinal nerve
→ Spinal cord posterior grey horn
→ Interneuron to anterior grey horn
→ Ventral root of spinal nerve
→ Motor efferent neuron
→ Effector organ (part of the body that will respond to the stimulus)

What structure connects the right hemisphere of the brain to the left hemisphere of the brain?

Corpus Callosum

The hemisphere of the brain that is good at analyzing information in a linear path specializing in math, science and skills is the......?

Left Hemisphere

What fissure separates the cerebrum and cerebellum?

Transverse Fissure

What area of the brain (lobe) is the primary motor area?

Frontal Lobe

What area of the brain (lobe) is primary somatosensory?

Parietal Lobe

What area of the brain (lobe) is primary auditory?

Temporal Lobe

What part of the brain (lobe) is primary visual?

Occipital Lobe

The area of the brain primarily responsible for language comprehension is known as what area?

Wernicke's Area

Where do upper motor neurons originate and what path do they take during sensory/motor communication?

Motor neurons originate from the precentral gyrus of the frontal cortex:

-After integration, a motor command is sent from the precentral gyrus of the frontal cortex.

-The upper motor neuron sends an action potential down to the spinal cord.

Where does a lower motor neuron originate and what path does it take during the sensory/motor communication?

The lower motor neuron originates from the spinal cord: The axon of the lower motor neuron emerges from the spinal cord in a nerve and connects to a muscle to cause contraction of the target muscle.

What system in the brain is responsible for emotion and memory?

The Limbic system:
-Emotion and memory
-Gratification: sensations of pleasure or reward
-Aversion: sensations of fear or sorrow

What is the purpose of CSF?

It surrounds the brain and spinal cord;
buoyancy, protection, chemical stability

Where is CSF made?

1. Choroid Plexus
2. Ependymal Cells

CSF is reabsorbed through arachnoid granulations in the blood, eventually ending up in what structure of the brain?

The dural sinuses, which are veins in the brain

What structure within the Diencephalon is connected to the pituitary gland and controls endocrine functions and heat regulation?

The Hypothalamus

Where do the Cranial Nerves originate from?

The Pons

What structure in the brain stem controls the vital centers of cardiac, vasomotor and respiration?

The Medulla

What structure connects the two structures of the cerebellum?

The vermis

What is the function of the cerebellum?

-Equilibrium and balance
-Coordination of movement: it communicates with the motor areas of the cerebrum to smooth and coordinate movement

What subdivision of the PNS controls voluntary movements and reflexes?

The Somatic Nervous System

Specialized structures that detect changes in the environment are called what?

Sensory Receptors

Sensory Receptors in the organs are called what?

Visceral sensory receptors

Small bumps on the tongue that contain taste buds are called what?

papillae

Axons of the olfactory receptor neurons project through what bone structure?

Cribriform plate of the ethmoid bone

What is the purpose of the lacrimal apparatus?

-Contains the lacrimal gland, excretory lacrimal ducts, nasolacrimal duct
-Produces tears that lubricate, moisten, and protect the eye's surface, and drains excess tears from the eye

What structure of the eye has color, and can change the pupil size when stimulated by light?

The Iris; the pupil dilates in the dark and contracts in the light.

What structure is transparent and admits light into the eye?

The Cornea

What condition is caused by an elevated pressure within the eye due to improper drainage of aqueous humor?

Glaucoma

What type of receptor cells absorb light and generate electrical signals to the bipolar cells?

Photoreceptors

What happens at the optic chiasm?

-Optic nerve extends from posterior aspect of eye

-Some fibers cross at the chiasm: Right temporal field crosses into left visual cortex (vice versa) Right nasal field of vision enters Right visual cortex (vice versa)

-Optic tract propagate signals to occipital lobe

Cells activated by bright light that create sharp images that are high in acuity are called?

Cones

What is the purpose of the Eustachian Tube?

-Auditory tube
-Connected to pharynx
-Equalizes pressure in both sides of tympanic membrane

What is the purpose of the Oval window?

It is a membrane that carries sound vibrations from the middle ear to the inner ear

What part of the inner ear converts vibrations into nerve impulses?

The cochlea; specifically the organ of Corti

What division of the PNS controls cardiac muscle, smooth muscle and gland secretion?

The Autonomic Nervous System

How many Neurons does are in the ANS and what are they called?

Two; preganglionic and postganglionic, Acetylcholine (ACh) and Norepinephrine (NE)

What Neurotransmitters are released through the postganglionic neuron during a sympathetic nervous system response?

Epinephrine and norepinephrineor Acetylcholine (ACh)