Physiology Flashcards
What is the most serious problem associated with Marfan syndrome?
weakness of the aorta
What is fibrillin and what does it do?
glycoprotein; forms microfibrils which make up connective tissue (contain an elastin core)
What is the role of MFAP-4?
assembles fibrillin into microfibrils which eventually cross-link to make mature elastic fibers
What is the role of TGF-beta?
deleterious effects on vascular smooth muscle development and integrity of ECM; mutated fibrillin = excess TGF-β at lungs, heart valves, aorta
What is cystic medial degeneration?
in aorta; fenestrated membrane and smooth muscle cells replaced by amorphous ground substance
What is the genetic nature of Marfan syndrome?
autosomal dominant
What is the role of connective tissue?
1) support
2) protect
3) bind organs
What are the 3 components of connective tissue?
1) cells
2) protein fibers
3) ground substance
What is mesenchyme?
embryonic connective tissue derived from mesoderm; origin of (almost) all connective tissue cell types
What is the only type of connective tissue which mesenchymal stem cells do not differentiate into?
hematopoietic stem cells
Do lymphocytes arise from myeloid stem cells?
NO
Where do hematopoietic stem cells originate?
bone marrow
Which type of connective tissue forms tendons and ligaments?
dense regular connective tissue
Which type of connective tissue binds the epidermis to the underlying layers of skin?
dense irregular connective tissue
Which type of connective tissue forms the walls of elastic arteries sucha s the aorta
elastic connective tissue
Which tissue sub-types are made from loose connective tissue?
1) areolar
2) adipose
3) reticular
Which type of connective tissue makes the papillary layer of the dermis, subcutaneous layer, and surrounds organs, nerves, and blood vessels?
areolar loose connective tissue
Which type of connective tissue creates the subcutaneous layer of skin and surrounds/covers some organs?
adipose loose connective tissue
Which type of connective tissue is located at the spleen, lymph nodes, thymus, and bone marrow?
reticular loose connective tissue
Which tissue sub-types are made from cartilage?
1) hyaline cartilage
2) fibrocartilage
3) elastic cartilage
Which types of cells make up cartilage?
chondrocytes
What is the vascularity of cartilage?
avascular
Is cartilage protected by the immune system?
NO
Which types of fibers are in elastic cartilage?
elastic fibers
Where is elastic cartilage located in the body?
1) external ear
2) larynx
3) Eustachian tubes
What is another name for elastic cartilage?
yellow cartilage
What is the most common type of cartilage?
hyaline cartilage
Where is hyaline cartilage located in the body?
1) lines bones in joints (articular)
2) costal cartilages
3) epiphyseal plates
4) majority of fetal skeleton
What is chondromalacia?
increased friction between two articular cartilage surfaces in the early stages?
What is advanced stage chondromalacia?
arthritis
Which molecular characteristics do chondrocytes have to support their protein synthesizing activity?
1) extensive rough ER
2) well developed Golgi
What is the strongest form of cartilage?
fibrocartilage; most rigid
Where is fibrocartilage located in the body?
1) intervertebral discs
2) high stress areas such as pubic symphysis
3) conects tendons and ligaments to bone
What is a structure which fibrocartilage characteristically lacks?
perichondrium
What is chondrodystrophy?
group of disorders in which cartilage is ossified or transformed into bone
What is arthritis?
degeneration of cartilage in the joints. leading to limited movement and pain
What is achondroplasia?
cartilage disorder resulting from dwarfism
What is a chondroma?
benign tumor which arises in the cartilage
What is the role of the Volkmann’s canal?
connect osteons
What is the embryonic precursor to osteoblasts and osteocytes?
osteoprogenitor cell (mesenchymal stem cell)
What are the 2 types of fluid connective tissue?
1) blood
2) lymph
Blood stem cells divide into:
1) myeloid stem cells
2) lymphoid stem cells
What are the four qualities of sensation?
1) modality (burning, stinging, pressure)
2) location
3) intensity (sharp, dull, Scale 1-10)
4) duration/frequency
What is a receptive field?
part of the body which is feeling the sensation
Which order of neuron is first to penetrate the field in sensation?
first-order neuron
What is the role of the inhibitory receptive field in sensation?
EX: visual processing; important for contrast to better define where is the stimulus
What is the pathway of pain sensation?
pain sensor>spinal relay neurons>spinal cord>spinothalamic tract>thalamus>cerebral cortex
What is nociceptor?
simple sensory receptor with bare, free nerve ending
What are the types of nociceptors?
1) thermal
2) mechanical
3) polymodal
4) silent
What is the myelination and fiber type of thermal nociceptors?
small, thinly myelinated
A-delta fibers
What is the myelination and fiber type of mechanical nociceptors?
intense pressure to skin
A-delta fibers
What is the myelination and fiber type of polymodal nociceptors?
small, non-myelinated C fibers (slow) **high intensity mechanical, chemical, or thermal
What are silent nociceptors?
sensory receptors found in viscera which cause diffuse nociceptor activation but not pain
What affect do inflammation and chemical agents have on silent nociceptors?
reduce the firing threshold, causing them to fire at lower levels of stimulation
Why are there different types of nociceptors?
different types are sensitive to different sypes of sensation
What is a soma and where is it located?
cell body of a sensory neuron; located in the middle of the axon
What happens when the TRP channels are activated?
cause change in membrane potential of DRG cells
How is the potential generated in sensory receptors?
ions enter nerve ending through the transient receptor potential (TRP) channel
What happens if the sensory receptor potential stays above the threshold for a long period of time?
multiple action potentials will be generated
How can the intensity or duration of a sensation be altered?
1) generate multiple action potentials by having action potentials above the threshold
2) involve other nociceptors
3) involve other sensory receptors
What type of pain do A-delta fibers cause?
sharp
What type of pain do C fibers cause?
dull, aching
Which chemicals are responsible for pain production?
prostaglandins and bradykinin
How is pain produced?
prostaglandin and bradykinin sensitize nociceptors by activating A-delta and C fibers directly to increase the release + synthesis of prostaglandins from nearby cells
What causes inflammation after pain?
Calcatonin Gene Related Protein (CGRP) and Substance P are released from nerve endings upon injury and cause:
1) vasodilation
2) increase in histamine from mast cells
How is neurologic inflammation characterized?
triple response from Substance P
Where do A-delta fibers project in the spinal cord?
lamina I, II, V
Where do C fibers project in the spinal cord?
lamina I, II
Why do patients often mistake their heart attack for limb pain?
referred pain from the heart attack; convergence of fibers in the dorsal horn lead to an incorrect localization of pain and confused brain
What is the gate control theory of pain?
pain transmission can be disrupted with non-noxious stimulation (rubbing a stubbed toe)
How does the gate theory of pain explain reduction of pain?
convergence of the signal paths onto a projection neuron enables the disruption in the dorsal horn; projection neuron is not sending activation signal because of the peripheral stimulation
What innervates dermatomes?
individual peripheral nerves
Why does the gray matter change sizes as one moves throughout the spinal cord?
larger as one moves inferiorly; corresponds to amount of information each level is responsible for
What are the Brodmann numbers of the primary motor cortex?
4 [anterior to central sulcus]
What are the Brodmann numbers of the primary somatosensory cortex?
3, 1, 2 [posterior to central sulcus]
What is the pathway of motor information from the brain to the muscle?
cerebral cortex>corticospinal tract [motor cortex>brainstem>spinal cord>muscle]
What does information from the right cerebral cortex act on?
muscles on the left side
What is the posterior column-medial lemniscal pathway?
long sensory tract pathway; vibration, proprioception, light touch
What is the anterolateral pathway?
long sensory tract pathway; painful stimuli, temperature
Where is the second order neuron in the long sensory tracts?
dorsal column pathway: brainstem
anterolateral system: spinal cord
Where do the nerves in the long sensory tracts cross to the opposite side of the brain?
projection from the second order neuron
What is the dermatome for the upper cervical region?
neck
What is the dermatome for the lower cervical region?
arm
What is spinal shock?
all spinal reflexes are significantly depressed after a spinal cord injury; lasts at least 2 weeks
What minimizes the inflammatory response in spinal cord injury repairs?
acute treatment with glucocorticoids
What is radiculopathy?
sharp pain radiates down the leg caused by compression of a spinal nerve; HNP can impinge nerve
What is the innervation of the annulus fibrosus and nucleus pulposus?
they are not innervated
What is lumbar spinal stenosis?
narrowed lumbar spinal canal
