IB Biology Topic C3.1.9 Pain Reflex Arcs Revision Notes (SL/HL)

IB Biology Topic C3.1.9 Pain Reflex Arcs Revision Notes (SL/HL) | RevisionDojo

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Reflex Arcs Give Rapid, Automatic Responses by Bypassing the Brain

Definition

Reflex arc

A pathway followed by nerve impulses during a reflex action, including the sensory and motor neurons and sometimes an interneuron.

A reflex arc is a chain of neurons that carries a signal from a receptor to an effector.
It routes the signal through the spinal cord rather than the brain, which makes the response fast and automatic.

Analogy

Touch a hot stove and your hand jerks away before you even think about it.
This automatic reaction is a reflex, a rapid response that protects you from harm.

A Reflex Arc Has Five Components

Receptor: detects the stimulus, such as pain or heat.
Sensory neuron: carries the signal to the central nervous system.
Interneuron: relays the signal within the spinal cord.
Motor neuron: carries the response signal to the effector.
Effector: carries out the response, such as a muscle contraction.

The Pain Reflex Arc, Step by Step

Step 1: The Receptor Detects the Stimulus

Free sensory nerve endings in the skin act as pain receptors.

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Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Reflex Arcs Give Rapid, Automatic Responses by Bypassing the Brain

Definition

Reflex arc

A pathway followed by nerve impulses during a reflex action, including the sensory and motor neurons and sometimes an interneuron.

A reflex arc is a chain of neurons that carries a signal from a receptor to an effector.
It routes the signal through the spinal cord rather than the brain, which makes the response fast and automatic.

Analogy

Touch a hot stove and your hand jerks away before you even think about it.
This automatic reaction is a reflex, a rapid response that protects you from harm.

A Reflex Arc Has Five Components

Receptor: detects the stimulus, such as pain or heat.
Sensory neuron: carries the signal to the central nervous system.
Interneuron: relays the signal within the spinal cord.
Motor neuron: carries the response signal to the effector.
Effector: carries out the response, such as a muscle contraction.

The Pain Reflex Arc, Step by Step

Step 1: The Receptor Detects the Stimulus

Free sensory nerve endings in the skin act as pain receptors.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C3.1.9: Pain Reflex Arcs Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Reflex Arcs Give Rapid, Automatic Responses by Bypassing the Brain

A Reflex Arc Has Five Components

The Pain Reflex Arc, Step by Step

Step 1: The Receptor Detects the Stimulus

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Reflex Arcs Give Rapid, Automatic Responses by Bypassing the Brain

A Reflex Arc Has Five Components

The Pain Reflex Arc, Step by Step

Step 1: The Receptor Detects the Stimulus

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account