PHY-LEC-LE-1-07-Intro-to-Reflexes-and-ANS-V1

Somatic reflex.

Extrafusal fibers.

Almost autonomous; acts independently from sympathetic and parasympathetic nervous systems but can still be influenced by both.

Stimulus, receptor, sensory neuron, interneuron, motor neuron, and effector.

A reflex is an automatic response to a stimulus.

Round structures at the end of axons that release neurotransmitters.

Extrafusal fibers.

At the junction of the tendon and muscle fibers.

The head lifts up and the spine straightens, demonstrating the Landau reflex.

It refers to the preganglionic fibers that leave the spinal cord between T1 to L2.

A relatively predictable, involuntary, and nearly instantaneous response to an eliciting stimulus.

Fatigue causes a slight bending of the knee, stretching the knee extensor muscle and increasing the length of the muscle fiber.

A reflex that involves a single synapse.

Choline acetyltransferase (ChAT).

Length of the muscle, tension of the muscle, and the rate of change in length/tension.

Controls GI motility and movement of food from proximal to distal.

They are inhibitory and decrease cAMP levels.

Disynaptic synapses, first synapsing with an inhibitory neuron.

They cause constriction/contraction of smooth muscle by increasing IP3 and intracellular Ca+2.

They are present at birth, involuntary, and directed from the brainstem without cortical involvement.

Innate reflexes are present since birth and involuntary, while acquired reflexes are learned after birth and can be voluntary.

The degree of stretching of the muscle spindle.

They work together to oppose the decrease in contraction of the rectus femoris due to fatigue.

Myotatic/stretch reflex.

It causes relaxation of the muscle in response to increased tension.

The hands and legs extend in a protective fashion, demonstrating the Positive Support Reflex.

Acetylcholine (Ach).

Responsible for the fight or flight response.

A repetitive firing of excited neurons after the cessation of the stimulus.

Reflexes that keep our body upright and aligned, such as righting, parachute, and tonic neck reflexes.

Receptor, sensory neuron, interneuron, motor neuron, and effector.

From the esophagus until the anus.

They sense muscle length and the rate of change of length.

Myenteric Plexus and Submucosal Plexus.

Contraction of flexion muscles to remove the foot from the stimulus.

Sudden rapid stretch of muscle fibers.

Nuclear chain fiber.

It allows preganglionic fibers to synapse with postganglionic neurons at the same level or travel to other ganglia.

It breaks down acetylcholine in the synaptic cleft.

Energy conservation and maintenance of vital body functions.

The sympathetic nervous system.

Norepinephrine and epinephrine (80% of norepinephrine is converted to epinephrine in the adrenal medulla).

The muscle shortens due to leg extension, causing the muscle spindle to become lax, stopping excitatory discharge and leading to muscle relaxation.

The myotatic reflex is activated, exciting the α motor neuron of the homonymous muscle (rectus femoris).

Mucosa, Submucosa, Muscularis Propria, and Serosa.

It converts PIP2 to IP3 and DAG, increasing intracellular Ca+2 levels and causing contraction of smooth muscle.

Maintenance of posture and overcoming unexpected impediments during voluntary movement.

Preganglionic fibers are long, while postganglionic fibers are short.

Norepinephrine has a greater effect on alpha receptors compared to beta receptors (α > β).

Norepinephrine.

Glandular or non-skeletal muscular responses, including smooth muscles like the heart and blood vessels.

On postsynaptic effector cells, mainly in smooth muscle.

They are primarily found in the heart and are responsible for increasing heart rate and contractility.

Knee jerk reflex.

The Somatic Nervous System is voluntary with a single neuron from the CNS to effector organs, while the Autonomic Nervous System is involuntary with a two-neuron chain.

When the baby is abruptly lowered, the arms stretch out, hands open, and legs flex.

It serves as the basic circuitry that underlies a reflex.

The gastrointestinal tract.

The entrance of choline through the sodium-coupled choline transporter.

They are long.

Inside vesicles via the vesicle-associated transporter (VAT).

A part of the peripheral nervous system that governs the function of the gastrointestinal system.

The signal travels to sensory neurons, enters the spinal cord, and causes flexion of that foot while also sending a signal to the opposite leg to extend it.

To extend the opposite limb to support the body once the affected limb is withdrawn.

The pressure on the foot pads causes the limbs to extend.

They inhibit norepinephrine release from presynaptic receptors and cause dilation/relaxation by decreasing cAMP.

Drugs that stimulate the sympathetic nervous system.

It is diversely distributed to the eyes, heart, lungs, GI tract, and reproductive organs.

Cholinergic.

Sympathetic and Parasympathetic.

Eccrine sweat glands and some blood vessels have muscarinic receptors.

Nuclear bag muscle fibers.

It increases Ca+2 levels in the cytoplasm, leading to action potential and increased heart rate, inotropy, and AV conduction.

They transmit signals from the central nervous system to skeletal muscles.

Sympathetic prepares the body for 'fight or flight', while parasympathetic promotes 'rest and digest'.

They are excitatory and increase IP3 and intracellular Ca+2 levels.

Polysynaptic, due to the complexity of their circuitry.

Positive support reflex and Stepping reflex.

Cranial nerves III, VII, and IX.

The conversion of Tyrosine to Dopa by the enzyme tyrosine hydroxylase.

Stretch, blood chemicals, temperature changes, and other internal stimuli.

Sneezing, coughing, micturition, pupillary reflex, vomiting, swallowing, and some sexual reflexes.

Contracts meridional fibers, leading to pupil dilation (mydriasis).

When a finger is placed in a baby's hand, it causes the flexing of the fingers.

Adrenergic receptors (alpha or beta).

It causes a conformational change and activates the G protein, converting GDP to GTP.

There will be no negative feedback mechanism, helping to reverse the decrease in force caused by fatigue.

Sensory receptors.

A sudden contraction followed by relaxation.

A maintained stretch, such as standing up.

Mainly found in brown fats, but also present in the heart and urinary bladder wall.

Epinephrine has an equal effect on both alpha and beta receptors (α = β).

Spinal reflexes are processed in the spinal cord, while cranial reflexes are processed in the brain.

Type 1a sensory nerve fibers.

When a baby is held upright with one foot touching the surface, the hip and knee of that foot flex while the other foot steps forward.

Acetylcholine.

They cause relaxation by increasing cAMP.

Glandular and non-skeletal muscles.

If the perioral skin is stroked, the mouth opens, and the baby's head turns towards the stimulated side.

Nicotinic and Muscarinic.

Acetylcholine.

Somatic and visceral reflexes.

PKA inhibits Phospholipase C, resulting in inhibitory effects on smooth muscle.

It is a nociceptive or pain reflex.

It acts as a negative feedback mechanism to oppose changes in muscle tension.

They enter the white ramus and reach the paravertebral sympathetic chain of ganglia.

It is important for balance, allowing the other foot to support the body.

Alpha-receptors and Beta-receptors.

It causes rapid stretch of the rectus femoris muscle, leading to a knee-jerk reflex.

Lateral inhibition to sharpen motor signals.

A reflex that helps correct the position of the body when it goes off balance.

Contracts circular fibers, leading to pupil constriction (miosis).

The own nervous system of the gastrointestinal tract that can operate independently from the brain and spinal cord.

Ligand-gated ion channels.

Monosynaptic reflex.

They monitor the position of limbs, body movement, and tension in the musculoskeletal system.

They originate from the intermediolateral horns of the sacral nerves S2 to S4 and the brainstem.

Tendon tension and rate of change of tension.

Nuclear bag muscle fiber.

It dissociates and is broken down by Acetylcholinesterase.

Two neuron chains from the CNS to effector organs.

They work hand-in-hand to maintain balance and support during withdrawal.

It helps control muscle tension, regulates muscle force, and prevents excessive tension on muscles and tendons.

They increase cAMP, leading to excitatory effects in the heart, lipocytes, and brain.

Skeletal muscle fibers.

It does not have postganglionic fibers.

Pupillary light reflex.

Gray matter (butterfly-shaped).

They originate from the thoracic and lumbar regions.

In postsynaptic effector cells, specifically in bronchial, GI, uterus, urinary bladder wall, and cardiac muscle.

From the brainstem and sacral part of the spinal cord.

The entry of calcium ions when an action potential reaches the nerve terminal.

Regulates fluid homeostasis, including absorption or secretion of water and electrolytes.

Extension of the leg (jerky movement).

Annulospiral ending.

The vagus nerve (CN X).

It can be reuptaken, diffuse away, or be broken down by enzymes.

Drugs that stimulate the parasympathetic nervous system.

Optic cues (eyes), labyrinth cues (ears for equilibrium), and head orientation relative to the neck, thorax, and pelvis.

Intrafusal fibers.

8 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, 1 Coccygeal.

It activates the L-type Ca²⁺ channel, allowing Ca²⁺ to enter the cells.

Norepinephrine (NE).

They open Na+ and K+ channels, leading to excitatory effects and cell depolarization.

The Golgi tendon organ enhances the excitability of the α motor neuron going to the rectus femoris.

Type 1a fiber.

It serves as a special postganglionic neuron that secretes hormones into the bloodstream.

Cholinergic receptors, specifically nicotinic.

They are necessary for newborn survival and development.

Muscarinic receptor.

White matter.

The adrenal medulla does not have a postganglionic nerve fiber and secretes epinephrine and norepinephrine directly into the bloodstream.

Skeletal muscles.

1 nerve fiber.

Alpha motor neurons and gamma motor neurons.

2 nerve fibers (preganglionic and postganglionic).

When the baby's head is turned to one side, the arm and leg on that side extend while the opposite side flexes.

It activates protein kinase A, leading to various cellular effects.

Acetylcholine.

Inside the spinal column of the vertebrae.

Ascending Pathway from peripheral receptors to the dorsal nerve root.

Norepinephrine and epinephrine.

Motor neurons.

Muscarinic receptors.