Control of Body Movement and Autonomic Nervous System

These flashcards cover key vocabulary terms and concepts related to motor control, reflexes, and the autonomic nervous system, essential for exam preparation.

Descending motor pathways

Axons carrying motor commands from the brain to the PNS.

Flaccid paralysis

Loss of motor function due to severe damage to the ventral root or anterior horn cells.

Spastic paralysis

Loss of voluntary control with intact spinal neurons, causing irregular muscle stimulation.

Reflex

A rapid, predictable motor response to a stimulus.

Components of a reflex arc

1. Receptor, 2. Sensory neuron, 3. Integration center, 4. Motor neuron, 5. Effector.

Somatic reflexes

Reflexes mediated by the spinal cord involving skeletal muscles.

Autonomic reflexes

Reflexes mediated by the brain or spinal cord involving involuntary responses.

Monosynaptic reflex

A reflex involving a single synapse between a sensory and a motor neuron.

Polysynaptic reflex

A reflex involving multiple synapses with one or more interneurons.

Stretch reflexes

Reflex that involves muscle spindles detecting stretch in muscles.

Reciprocal inhibition

The process by which an excitatory signal to one muscle is accompanied by an inhibitory signal to its antagonist.

Flexor (withdrawal) reflex

A reflex initiated by a painful stimulus that causes withdrawal of a body part.

Superficial reflexes

Reflexes initiated by cutaneous stimulation.

Parasympathetic system

Division of the autonomic nervous system responsible for rest and digest functions.

Sympathetic system

Division of the autonomic nervous system responsible for fight or flight responses.

Dual innervation

Most internal organs are innervated by both autonomic divisions.

Cholinergic fibers

Neurons that release acetylcholine (ACh).

Adrenergic fibers

Neurons that release norepinephrine (NE).

Efferent division

The part of the nervous system responsible for carrying motor commands from the CNS.

Somatic nervous system

The division of the efferent system that controls voluntary movements of skeletal muscles.

Autonomic nervous system

The division of the efferent system that controls involuntary functions.

Preganglionic neuron

The neuron that extends from the CNS to a ganglion.

Postganglionic neuron

The neuron that extends from a ganglion to the effector.

Thoracolumbar anatomy

The sympathetic division's structure, emerging from the thoracic and lumbar regions.

Craniosacral anatomy

The parasympathetic division's structure, emerging from the brainstem and sacral regions.

Collateral (prevertebral) ganglia

Ganglia located anterior to the vertebral column in the sympathetic division.

Paravertebral ganglia

Ganglia running parallel to the vertebral column in the sympathetic division.

Epinephrine release

Triggered by the sympathetic nervous system from the adrenal medulla.

Ach

Acetylcholine, a major neurotransmitter in the autonomic nervous system.

NE

Norepinephrine, a major neurotransmitter in the sympathetic nervous system.

Locally activated parasympathetic effects

Generally short lived and confined to few target organs.

Wide spread sympathetic effects

Longer lasting effects covering multiple areas of the body.

Sympathetic tone

The state of partial constriction of blood vessels due to sympathetic activity.

Muscarinic receptors

Receptors that bind Ach found on parasympathetic effectors.

Nicotinic receptors

Receptors that bind Ach found on motor end plates and postganglionic neurons.

Alpha receptors

Adrenergic receptors responsive to NE, mainly causing stimulation.

Beta receptors

Adrenergic receptors responsive to NE and E; include subtypes with excitatory and inhibitory functions.

Sympathomimetic agents

Drugs that enhance sympathetic responses.

Parasympatholytic agents

Drugs that decrease parasympathetic responses.

Tricyclic antidepressants

Drugs that prolong the activity of NE, being sympathomimetic.

Beta-blockers

Drugs that block cardiac beta receptors, thus decreasing heart rate.

Alpha-blockers

Drugs that interfere with vasomotor fibers to treat hypertension.

Salbutamol

A drug that activates beta-2 receptors to dilate bronchioles in asthma.

Orthostatic hypotension

Low blood pressure upon positional changes due to slow sympathetic response.

Visceral reflexes

Reflex responses related to organ functions like micturation and defecation.

Integration center of reflexes

The site within the CNS where sensory input is processed.

Glandular effectors

Effectors like glands that are targeted by the autonomic nervous system.

Target organ

The specific organ that an effector acts upon.

Neurotransmitter effects

Can be either excitatory or inhibitory depending on receptor types.

Efferent neurons

Nerve cells that carry messages away from the brain and spinal cord.

Sensory neurons

Nerve cells that carry information to the CNS.

Integration neurons

Interneurons that facilitate communication between sensory and motor neurons.

Splanchnic nerve

Nerve carrying sympathetic fibers to the abdominal organs.

Pupil dilation

A sympathetic response to increase light entering the eye.

Cardiac output

The amount of blood the heart pumps in a given period.

Blood pressure regulation

Managed by the autonomic nervous system through sympathetic tone.

Sweating response

Initiated by sympathetic activation to cool the body.

RBC production

Enhanced by the sympathetic nervous system during emergencies.

Involuntary control

Control over muscles and glands not subject to conscious thought.

Preganglionic synapse

The connection point where a preganglionic neuron meets a postganglionic neuron.

Short postganglionic fibers

Found in the parasympathetic division, extending to target organs.

Long postganglionic fibers

Found in the sympathetic division, extending to target organs.

Cardiac functions

Includes regulation of heart rate and blood pressure by the autonomic nervous system.

Pulmonary functions

Involves controlling breathing rate and bronchiole diameter.

Gastrointestinal activity

Managed by the autonomic nervous system to regulate digestion.

Chemical digestion

The breakdown of food substances chemically in the digestive tract.

Micturation reflex

Reflex that facilitates urination.

Facilitation vs Inhibition

Refers to how neurotransmitters can either stimulate or suppress organ functions.

Absorption and secretion regulation

Managed by the autonomic nervous system in various organs.

Sympathetic effects on blood vessels

Includes constriction leading to increased blood pressure and flow regulation.

Parasympathetic effects on digestive organs

Includes enhancement of secretions and digestive activity.

Stimulation of gland activity

Managed by parasympathetic divisions within the autonomic system.

Epinephrine's role in stress response

Prepared the body for rapid metabolic needs during emergencies.

Norepinephrine's role in blood pressure

Essential for maintaining vascular tone and pressure.

Acetylcholine's role

Key neurotransmitter for both sympathetic and parasympathetic preganglionic neurons.

Synaptic transmission

The process by which neurotransmitters are released from one neuron to another.