Detecting & regulating change Flashcards
What is receptor ?
Receptor is a structure or cell that detects a stimulus
The sensations provided by receptors are categorized as either:
- Somatic senses/ sensations
- Special senses/ sensations
What is somatic senses ?
Originate from receptors present at more than one location in the body
What are the examples of somatic senses ?
For example: temperature, touch, vibration, pressure, pain
What is special senses ?
Originate from receptors that are restricted to a particular areas of the body (dedicated organs)
What are the example of special senses ?
For example:
Sight (the eyes)
Taste (the tongue)
Sound (the ears)
Where is the thermoreceptors located ?
Hypothalamus and skin
What stimulates the thermoreceptors ?
Changes in temperature
How does thermoreceptor works?
The hypothalamus then regulates the body temperature based on the signals from these receptors
Where is the osmoreceptors located ?
hypothalamus
What stimulates the osmoreceptors ?
changes in osmotic pressure
How does osmoreceptor works?
The hypothalamus then maintains the blood osmotic pressure within the tolerable limit based on the signals from these receptors
Where is the chemoreceptors located ?
Located in the nose (detect odour ) and tongue (sense taste)
Chemoreceptors that monitor blood pH are located in the medulla oblongata, aortic and carotid bodies
Where are touch receptors located?
Receptors that detect a light touch or vibration are close to the surface of the skin
Receptors that respond to stronger pressure and vibrations are in deep skin layers
Where are pain receptors located?
Mainly found in the skin and mucous membranes
What is the other name for pain receptors?
nociceptors
What are the pain receptors stimulated by?
Stimulated by damage to tissues, such as from cut, or excessive heat or chemicals
Why is pain receptors important?
The ability to perceive pain is essential for survival - warns us to avoid certain stimuli and informs us of injuries
What is reflexes?
A reflex is a rapid, automatic response to a change in the external or internal environment.
What are the four main important properties of reflex?
- A stimulus is required to trigger a reflex – the reflex is not spontaneous.
- A reflex is involuntary-it occurs without any conscious thought.
- A reflex response is rapid – only a small number of neurons are involved.
- A reflex response is stereotyped – it occurs in the same way each time it happens.
What is reflex arc ?
Reflex arc (the neural pathway involved in accomplishing reflex activity) components
Explain the pathway of reflex arc?
- Receptor - detects stimulus and produces an action potential
- Sensory neuron - Relays the impulse from receptor to the CNS
- Synapse – The information is passed on to other neuron via synapse. May involve more than one synapse depending on the type of reflex
- Motor neuron – Relays the impulse from CNS to the effector
- Effector – Carries out response
Explain the Flex & crossed extensor reflexes
- Stepping on sharp object activates pain receptors _ produce action potentials in sensory neurons travelling to the spinal cord
- Sensory neurons stimulate interneurons within the spinal cord _ interneurons transmit signals to motor neurons in the leg
- Some send signals to flex appropriate muscles to lift the foot (flex reflex), some send signals to extend muscles in the other leg (crossed extensor reflex)
Explain the Patellar reflex
- A tap just below the knee stretches the thigh muscle
- The stretch is detected by sensory nerves _ sensory nerves send signals to the spinal cord
- Motor neurons are activated
- Signals flow from the spinal cord back to the leg
- Leg jerks in respons
