PNS Chapter 13 Flashcards
Meninges in PNS
1) Dura Mater: outermost layer
2) Arachnoid mater: thin and wispy
3) Pia mater: bound tightly to surface.
Pia mater
- Forms the Filum Terminale (anchors spinal cord to coccyx)
- Forms the denticulate ligaments that attache the spinal cord to the dura mater
Epidural space
- Spinal epidural is done between L3 and S1
- Spinal tap or epidural is done to inject medications into the cerebrospinl fluid, particularly for spinal anesthesia or chemotherapy
- Epidural is don to collect cerebrospinal fluid, particularly for spinal when meningitis is suspected.
- Between the bony vertebrae and spinal dura mater; filled with soft padding of fat and a network of veins
Subdural space
- Filled with Serous fluid
- The space appears to be widest in the cervical region
- however, that the spinal subdural space is not a “potential” space at all, but that it occurs as a result of tissue damage which creates a cleft in this area of the meninges
Superior Sagittal Sinus
- CSF is absorbed into the dural venus sinuses via the arachnoid villi.
- dural venus sinuses collect venous blood from the brain and direct it into the internal jugular veins of the neck. It has no valves.
Arachnoid villi
- knoblike projections of the arachnoid mater that protude superiorly through the dura mater into the superior sagittal sinus.
- This villi absorb CSF into the venous blood of the sinus
Receptors classification by Stiumulus type
- Mechanoreceptors
- Thermoreceptors
- Photoreceptors
- Chemoreceptors
- Nociceptors
Mechanoreceptors
Respond to touch, pressure, vibration, stretch, and itch
Thermoreceptors
- Sensitive to changes in temperature (warm and cold)
- Cold receptors: (10 -40 °C); in superficial dermis
- Heat receptors: (32 - 48 °C); in deeper dermis
Photoreceptors
Respond to light energy (e.g retina)
Chemoreceptors
Respond to chemicals (e.g. smell, taste, changes in blood chemistry)
Nociceptors
Sensitive to pain-causing stimuli (pinching, capsaicin, extreme heat or cold)
Propioceptor
A sensory receptor, found chiefly in muscles, tendons, joints, and the inner ear, that detects the motion or position of the body or a limb by responding to stimuli arising within the organism.
Receptors classification by Location
- Exteroceptors
- Interoceptors
- Propioceptors
Exteroceptors
- Respond to stimuli arising outside the body receive external stimuli
- Hearing, vision, smell, taste, touch, pressure, pain, vibration, and temperature