Topics of Lecture Exam 5 Ch 12-14

CNS is composed of what structure?

The central nervous system is composed of the brain and spinal cord, along with gray and white matter

Define touch receptor

A sensory receptor that monitors changes in the internal and external environment. Found on the skin.

2 Major Control Body Systems

The nervous regulates body activities by responding using nerve impulses, and the endocrine system responds by releasing hormones.

Sensory Function (Nerv Function)

Sense changes in the external and internal environment via sensory receptors. Sensory neurons receive info from the outside like a ringtone.

Integrative Function (Nerv Function)

Analyzes the sensory info. stores some aspects, and acts accordingly. Interneurons serves this function.

Motor Function (Nerv Function)

Respond to the stimuli by initiating action. Motor neurons receive the info from other neurons and sends an action to effectors (muscle) that produce a response (contraction)

Function of Dendrite

Tree like extension that receive and input portions of a neuron. Receive the message and transport to the rest of the cell.

Examples of Ion Channels

Four types of channels in the production of an electrical signal in neurons: leak channels, Mechanically gated, ligand-gated, and voltage-gated channels

Leak Channels (ion)

Found in all cells and randomly alternate between open and closed. The plasma membrane’s permeability to potassium much higher than sodium.

Ligand-gated Channel (ion)

Found in the dendrites of sensory neurons and dendrites and cell bodies of motor and interneurons. Opens and closes in response into ligand (chemical) stimulus.

Mechanically gated Channel (ion)

Found in auditory receptors, touch and pressure receptors in skin. Opens and closes in response to mechanical stimulation such as vibrations and tissue stretching.

Voltage gated Channel (ion)

Participate in the generation and conduction of nerve impulses in the axons of all neurons. Open in response to change in membrane potential (voltage).

Subarachnoid Space

Contains cerebrospinal fluid that cushions the central nervous system, provides buoyancy, and aids in waste removal.

How many numbered paired of spinal nerves

31 pairs: 8 Cervical, 12 thoracic, 5 lumbar, 5 sacrum, and 1 coccyx

Nerve Plexus that supplies abdominal wall?

Lumbar in the lower back that supplies the abdominal wall, anterior thigh and genitalia.

Reflex arc structure that monitors body conditions?

Sensory neuron monitors body conditions. Axon conducts impulses from receptor to integrating center

Characteristics of a reflex

Requires stimulation, quick, involuntary, and are stereotyped.

Layer surrounding the entire spinal nerve?

Epinerium; superficial covering over entire nerve

Pain Receptor

Nociceptor; pain receptor, free nerve ending

Effector in Reflex Arc

Changes body condition levels such as muscles or gland that respond to motor nerve impulses.

Motor, Sensory, and Integrative

Sensory receptors in the PNS detect internal or external stimuli. This info is sent to the brain and spinal cord (CNS) where the sensory info is processed and respond accordingly known as integration. The analyzed info is then sent to effectors like muscle activating them in the final step motor function.

Motor function parts of the PNS

Divided into sensory and motor divisions where sensory receptors of the PNS send info to the CNS which analyzes and sends info to motor units in the PNS to make an action. PNS has somatic and autonomic motor systems.

Largest Part of the Brain

Cerebrum (brain part) that is called the “seat of intelligence” as it provides us with the ability to read, write, and speak. Allows one to remember the past and plan the future.

Define Blood Brain Barrier (BBB)

Protects brain from harmful substances and pathogens

Part of brain that controls heart rate and blood along with housing the respiratory center responsible for vomiting, coughing, swallowing, sneezing and hiccuping?

Medulla Oblongata

Define Pons

Both sensory and motor tracts, responsible for secondary control of respiration. Helps control breathing and both motor or sensory impulses both pass through pons.

How much blood supply goes to the Brain?

At any given time, there is 20% blood supply to the brain.

Define Reticular Formation

Net like region of white/gray matter that extends through the brain maintaining consciousness. This is mainly done by the RAS (reticular activity system), sensory axons that project to the cerebral cortex.

Define Thalamus

Relays almost all sensory input to cerebral cortex. Plays role in maintenance of consciousness.

Cerebellum Function

Second largest part of the brain that coordinate smooth movements of skeletal muscle, subconscious aspects of skeletal muscle, Regulates Posture and Balance, and equilibrium balance.

What are the lobes of the brain?

Front, Parietal, Temporal, and Occipital lobe.

Define Broca’s area

Cerebral cortex sensory area that’s responsible for speech.

Define Vagus (X) Nerve

Sensory area responsible for regulating visceral activity. Mixed cranial Nerve

Define Oculomotor (III) Nerve

Motor Cranial nerve that originates in the midbrain and controls movements of the eyeball and upper eyelid

Cranial Nerve(s) responsible for movement of the eyeball?

Oculomotor (III), Trochlear (IV), and abducens (VI) nerves.

Define Trigeminal (V) Nerve

Largest cranial nerve that contains motor axons that supply muscles of massification.

Define Trochlear (IV) Cranial Nerve

A motor cranial nerve that is the smallest cranial nerve and is found in the midbrain. Controls movement of eyeball.

Define Hypoglossal (XII) Nerve

Motor cranial nerve that conducts nerve impulses for speech and swallowing.

Repair and the Nervous System?

Limited ability for repair with the PNS being able to repair damaged dendrites or axons, whilst CNS is unable to make any repairs.

Factors that affect Propagation Speed?

Amount of myelination, axon diameter, and temperature,

Estimate of number of neurons in the human body?

Over 100 billion neurons in the body

Part of the brain that assists with breathing?

The pons and respiratory medulla Oblongata.

Define Nociceptor

Pain receptor, free nerve ending

Define Action Potential

Short-lasting event in which the electrical potential of a cell rapidly rises and falls

Define Ion Channels

Open and close due to gates allowing only ions to move across the plasma membrane

Repair and the PNS

In PNS, damage to dendrites and myelinated axons may be required if the cell body remains intact and if the schwanna cells that produce myelination remain active.

Various Flexes (4)?

Stretch (monosynaptic, contraction in response to muscle stretching), Tendon (polysynaptic, override stretch when tension is great preventing tear), Flexor (polysynaptic, response to painful stimuli causing one’s body to withdraw), Crossed Extensor (polysynaptic, helps maintain balance by extending the opposite leg).

Define Descending Tracts

They are motor tracts that carry nerve impulses from the brain to other parts of the body

Number of thoracic spinal nerves?

12 matching the 12 5thoracic vertebrae

Define Vestibulocochlear (VIII) Nerve

Sensory cranial nerve that connects the inner ear to the brainstem, controlling hearing and balance.

Define Ipsilateral

On the same side of the body as another structure. Ipsilateral reflex sees the motor and sensory neurons on the same side of the spinal cord

Bran Stem Components

Spinal Cord, Medulla Oblongata, pons, and Midbrain. From distal to proximal end.

Examples of Ions

Chlorine, Sodium, Potassium, and Calcium

Touch receptor (Capscule)

Meissners