Physio V 3

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Questions and Answers

What is one function of the spinal cord?

Regulation of hormonal levels

Processing visual stimuli

Memory retention

Coordination of reflex actions (correct)

Which region of the brain is primarily responsible for reflexes?

Cerebellum

Thalamus

Medullary region and pons (correct)

Cerebral cortex

What is a consequence of damage to the cerebellum?

Loss of motor coordination (correct)

Enhanced memory function

Decreased sensitivity to pain

Improved balance

What type of information does the cerebellum primarily receive?

Afferent information from various body parts Signup and view all the answers

Which part of the brain is involved in hormonal regulation?

Hypothalamus Signup and view all the answers

What is the primary function of the thalamus?

Relaying sensory information to the cortex Signup and view all the answers

Which region of the brain is involved in motor hierarchy?

All of the above Signup and view all the answers

What happens during spinal shock?

Immediate loss of all spinal functions Signup and view all the answers

What type of receptors do direct circuit neurons in the striatum have?

D1 receptors Signup and view all the answers

What is the effect of dopamine binding to D2 receptors in the striatum?

Inhibition of indirect circuit neurons Signup and view all the answers

When the idea of movement is generated in the cerebral cortex, what is one of the actions that takes place?

It sends impulses to striatum and through substantia nigra Signup and view all the answers

Which part of the globus pallidus is inhibited by striatum neurons in the indirect circuit?

External globus pallidus Signup and view all the answers

What happens to the thalamic nuclei when striatum neurons are activated in the direct circuit?

They increase activity Signup and view all the answers

What is the primary function of the basal ganglia in motor control?

To control voluntary movement through inhibition and excitation Signup and view all the answers

Which part of the substantia nigra is involved in the common functions with the internal globus pallidus?

Reticular part Signup and view all the answers

What type of neurons in the basal ganglia use GABA as a neurotransmitter?

Inhibitory neurons Signup and view all the answers

Where does incoming information to the striatum predominantly come from?

Cerebral cortex and substantia nigra compact part Signup and view all the answers

What is the effect of the direct circuit in the basal ganglia's function on movement?

Promotes disinhibition, leading to stimulated movements Signup and view all the answers

Which neurotransmitter is associated with the excitatory blue neurons in the basal ganglia?

Glutamate Signup and view all the answers

What role do the neurons in the secondary and tertiary motor areas play in movement?

They send information to the striatum to plan movement. Signup and view all the answers

What does dopamine do in relation to the D1 receptor in the basal ganglia?

Causes excitation of target neurons Signup and view all the answers

What is a primary effect of the degeneration caused by Huntington's chorea?

Degeneration of the caudate nucleus Signup and view all the answers

Which treatment option is specifically mentioned as a means to help normalize the activity of basal ganglia?

Deep brain stimulation Signup and view all the answers

How does Huntington's chorea affect the indirect circuit in the brain?

Weakens inhibition of the external globus pallidus Signup and view all the answers

What is a potential side effect of prolonged use of methyl-dopa?

Necessity for increased dosage Signup and view all the answers

What is a common characteristic of the facial expressions observed in individuals with certain cognitive impairments?

Masked facial expressions Signup and view all the answers

What happens to impulse transmission through corticospinal pathways when thalamus activity decreases?

It decreases. Signup and view all the answers

What is the primary effect of the basal ganglia during movement?

They specifically activate one motor program while inhibiting similar movements. Signup and view all the answers

Which of the following can contribute to the development of Parkinson's disease?

Genetic inheritance. Signup and view all the answers

What is one of the signs of Parkinson's disease?

Loss of ability to initiate voluntary movement. Signup and view all the answers

How does damage to the substantia nigra affect the direct circuit involved in movement?

It weakens activation of striatum neurons. Signup and view all the answers

What posture is commonly associated with individuals suffering from Parkinson's disease?

Stooped posture. Signup and view all the answers

What role do dopaminergic neurons play concerning cognitive abilities in Parkinson's disease?

Their loss leads to cognitive inabilities and dementia. Signup and view all the answers

What is the immediate effect on spinal cord neurons after transection?

Complete loss of function below the transection site Signup and view all the answers

What occurs to neurotransmitter levels shortly after the transection process?

They increase in remaining functional synapses Signup and view all the answers

What effect does the loss of substania nigra neurons have on the indirect circuit?

It enhances the suppression of movements. Signup and view all the answers

What happens to the thalamus when internal globus pallidus neurons are over-activated?

It cannot activate the motor cortex. Signup and view all the answers

What is the first sign of spinal shock?

Anesthesia Signup and view all the answers

What is one potential outcome of genetic inheritance related to Parkinson's disease?

Degeneration of substantia nigra neurons. Signup and view all the answers

Which of the following correctly describes paralysis post-transection?

Loss of conscious movements due to corticospinal tract damage Signup and view all the answers

What change occurs with reflexes below the transection site over time?

They initially disappear but later become hyperreflexive Signup and view all the answers

What is atonia in the context of spinal cord injuries?

Loss of skeletal muscle tone due to loss of reflexes Signup and view all the answers

How does autonomic reflex behavior change following spinal transection?

They return after some time and may become hyperactive Signup and view all the answers

Which spinal nerves primarily control blood vessel tone in response to spinal cord injury?

Thoracic nerves T1-L3 Signup and view all the answers

What reflects the change in muscle tone following a spinal cord injury?

Hypertonia develops in unaffected muscles Signup and view all the answers

What mechanism leads to hyperreflexia after spinal shock?

Reestablishment of synaptic connections after an initial loss Signup and view all the answers

Which statement about the recovery of synaptic function after spinal transection is false?

All spinal reflexes are permanently lost Signup and view all the answers

What is a potential consequence of a loss of sympathetic reflex control post-transection?

Decreased blood pressure leading to shock Signup and view all the answers

What occurs to spinal cord neurons over time following the loss of excitability?

They become hyperexcitable Signup and view all the answers

Study Notes

Central Nervous System (CNS)

The CNS is comprised of the brain and spinal cord
Motor hierarchy arranges brain centers into three levels based on their function in movement regulation.

Motor Hierarchy

Highest level: Secondary and tertiary cortical areas generate general movement plans.
Middle level: Primary cortical areas and subcortical structures (basal ganglia, brainstem nuclei, cerebellum) refine and organize the general plan into specific programs.
Lowest level: Lower motor neurons in the spinal cord execute the movement plans and initiate muscle contractions.

Spinal Cord Functions

White matter: Comprised of nerve fibers forming conductive pathways.
Grey matter: Contains nerve cell bodies and synapses.
Conductive function: Carries information up (ascending pathways) and down (descending pathways) the spinal cord.
Reflex function: Responsible for reflexes organized through the spinal cord.

Reflexes

Stretch reflexes: Triggered by muscle stretch, causing muscle contraction.
Tonic stretch reflex: Stimulated by slow stretch (gravity), causing weak muscle contraction.
Flexor reflexes: Triggered by painful stimuli, causing flexion of the affected limb.
Nociceptive reflex: Realized by pain receptors.
Crossed extensor reflex: Painful stimuli cause contraction of flexor muscles in one extremity, while simultaneously extending the other extremity.
Positive support reaction: Observed during transitions from a sitting to a standing position.
Rhythmic reflexes: Observed in walking, running, and swimming.
Autonomic reflexes: Realized through autonomic centers in the lateral horns of the spinal cord.

Early and Late Consequences of Spinal Shock

Spinal shock is a temporary loss of function below the site of spinal cord injury after damage.
Consequences vary based upon the level of the transection.

Functions of the Medullary Region and Pons

The medulla oblongata and pons are vital reflex centers controlling:
Breathing reflexes: Control inspiration and adjusts respiration based on respiratory gas changes
Cardiac control: Controls heart rate adjustments in response to blood pressure
Vasomotor control: Controls blood vessel diameter to maintain blood pressure
Defense reflexes: Coughing and sneezing protect respiratory system from foreign substances
Other reflexes: Vomiting, swallowing.

Functions of the Midbrain

Serves conductive and reflex functions related to visual and auditory systems

Functions of the Cerebellum

Regulates motor activities before impulses from the periphery reaches the brain
Plays a crucial role in:
Equilibrium control: Controls the intensity and duration of muscle contractions.
Proprioception: Awareness of body position
Coordination of movements: Coordinates agonist and antagonist muscle contractions.
Emotional behavior: Plays a role in emotional behavior
Damage: Leads to loss of motor control (mostly)

Afferent Information to the Cerebellum:

The cerebellum receives information from everywhere to be aware of current and planned movement.
Essential information comes from:
Cerebral cortex
Reticular activating system
Vestibular receptors
Olivary nuclei
Hearing & photoreceptors
Spinal cord

Functional Parts of Cerebellum

Anatomically divided into three lobes
Functional divisions within the lobes: vermis, intermediate, and lateral zones
Cerebellar cortex composed of three layers

Functions of the Thalamus

The thalamus relays sensory and motor information and plays a key role in attention and emotions.
Specific nuclei within the thalamus forward sensory (auditory, visual, touch) as well as motor information into the cerebral cortex.
A wide network of connections between various brain centers is important to integration function

Functions of the Hypothalamus

Coordinates the activities of the sympathetic and parasympathetic nervous systems
The hypothalamus has a number of centers regulating different aspects of behavior:
Thirst
Hunger and satiety
Sleep
Temperature regulation
Sexual functions
Stress
Biological rhythms

Damage of Pons and Medullary Region

Damage can lead to death due to traumatic incidents, tumors, or intracranial pressure increases.
Results in various neurological deficits (e.g., loss of vital functions like respiration, and blood pressure control).

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Description

Test your knowledge on the various functions of the brain and spinal cord with this quiz. It covers crucial aspects such as reflexes, motor control, and the roles of different brain regions. Perfect for students studying neuroscience or related fields.