Neurophysiology

Front 1

Autonomic nervous system

Back 1

Sympathetic: T1-L3 (thoracolumbar)

Parasympathetic: cranial nerves and S2-S4 (craniosacral)

Front 2

Nicotinic receptors

Back 2

🔹Na+/K+ channels

🔹NN: autonomic ganglia and adrenal medulla, blocked by hexamethonium

🔹NM: skeletal muscle, blocked by curare

Front 3

GProtein Receptors

Back 3

α1 Gq K M1 Gq K

α2 Gi I M2 Gi I

β1 Gs S M3 Gq CK

β2 Gs S

Front 4

α1 receptors

Back 4

🔹Vascular smooth muscle of the skin and splanchnic regions;

🔹GI and bladder sphincters;

🔹Radial muscle of the iris.

Front 5

α2 receptors

Back 5

🔹Walls of the GIT (relaxation)

🔹⬇️insulin release

Front 6

β1 receptors ❤️

Back 6

⬆️Heart

⬆️SA node, AV node, ventricular muscle.

Front 7

β2 receptors

Back 7

🔹Vascular smooth muscle of skeletal muscle 💪🏻

🔹Bronchial smooth muscle

🔹Walls of the GIT and bladder

Front 8

Muscarinic receptors

Back 8

M1: CNS

M2: Heart

M3: Glands, smooth muscle

Antagonist: atropine

Front 9

Drugs that act on the ANS

Back 9

Back (Definition)

Front 10

Effect of the ANS on organ systems

Back 10

Back (Definition)

Front 11

Nerve fiber types

Back 11

I'm

Front 12

Dorsal column system

Back 12

🔹Fine touch, pressure, two-point discrimination, vibration and proprioception.

🔹Group II fibers

🔹Ascend ipsilaterally to the nucleus gracilis and cuneatus of the medulla, where they cross toward the thalamus.

Front 13

Anterolateral system

Back 13

🔹Temperature, pain and light touch.

🔹Group III and IV fibers

🔹2nd neuron ascends contralaterally to the thalamus

Front 14

Nociception

Back 14

🔹Receptor: free nerve endings

🔹Substance P: inhibited by opioids

🔹Fast pain: group III fibers (localized)

🔹Slow pain: C fibers (poorly localized)

Front 15

Refractive errors

Back 15

🔹Hypermetropia: light focuses behind the retina (convex lens)

🔹Miopia: light focuses in front of the retina (biconcave lens)

🔹Astigmatism: curvature of the lens not uniform (cylindric lens).

Front 16

Layers of the retina

Back 16

🔹Pigment epithelial cells: convert 11-cis retinal to all-trans retinal.

🔹Receptor cells: rods and cones are not present on the optic disk (blind spot).

Receptor cells ➡️ Bipolar cells ➡️ Ganglion cells (optic nerve)

Front 17

Functions of Rods and Cones

Back 17

Back (Definition)

Front 18

Functions of Rods and Cones

Back 18

Back (Definition)

Front 19

Optic pathways

Back 19

Optic nerve ➡️➡️ Lateral geniculate body of the thalamus ➡️➡️ Geniculocalcarine tract ➡️➡️ Occipital lobe of the cortex

Front 20

Lesions of the geniculocalcarine tract causes...

Back 20

Homonymous contralateral hemianopia, just like lesions of the optic tract, but with macular sparing.

Front 21

Lesions of the optic pathways

Back 21

Back (Definition)

Front 22

Photoreception in rods

Back 22

Back (Definition)

Front 23

Organ of Corti

Back 23

Back (Definition)

Front 24

Central auditory pathways

Back 24

Lateral meniscus ➡️ Inferior colliculus ➡️ Medial geniculate nucleus of the thalamus ➡️ Auditory cortex

🔹Fibers may be crossed or uncrossed

🔹Tonotopic representation at all levels of the pathway

Front 25

Olfactory receptor cells

Back 25

🔹True neurons located in the olfactory epithelium

🔹Basal cells are undifferentiated stem cells that continuously turn over

🔹The only neurons in the adult that replace themselves

🔹Activate G proteins (⬆️cAMP)

Front 26

CN I (olfactory)

Back 26

🔹Unmyelinated C fibers

🔹Olfactory epithelium inervated by CN V (noxious stimuli, such as ammonia)

🔹Pass through the cribiform plate, whose fracture causes anosmia, but still responds to ammonia.

Front 27

Mitral cells in the olfactory bulb

Back 27

🔹Second-order neurons

🔹Forms the olfactory tract, which projects to the prepiriform cortex.

Front 28

Taste

Back 28

🔹Receptors are not neurons

🔹Anterior 2/3 of the tongue: salty, sweet and umami. CN VII

🔹Posterior 1/3 of the tongue:

sour and bitter. CN IX

🔹Back of the throat and epiglottis: CN X.

🔹CNs ascend in the solitary tract to solitary nucleus and to taste cortex.

Front 29

Muscle spindle

Back 29

🔹Muscle spindle reflexes oppose increases in muscle length.

🔹ɣ-motoneurons adjust the sensitivity of the muscle spindle so that it will respond appropriately during muscle contraction.

Front 30

Muscle reflexes

Back 30

Back (Definition)

Hint 30

Knee-jerk reflex

Front 31

Spinal shock

Back 31

Immediately after transection, there is loss of the excitatory influence from α- and γ-motoneurons. Limbs become flaccid and reflexes are absent.

Front 32

Cervical lesions

Back 32

C7: loss of sympathetic tone to the heart. ⬇️HR ⬇️ BP

C3: disconnection of respiratory muscles. 🚫breathing

C1: death (e.g., as a result of hanging)

Front 33

Transections above the spinal cord

Back 33

⬆️ Lateral vestibular nucleus: decerebrate rigidity (removal of inhibition from higher centers).

⬆️ Pontine reticular formation: decerebrate rigidity (remove of central inhibition)

⬆️ Midbrain: decorticate posturing and intact tonic neck reflexes.

Front 34

Cerebellum

Back 34

🔹Vestibulocerebellum: balance and eye movement.

🔹Pontocerebellum: planning and initiation of movement.

🔹Spinocerebellum: synergy (rate, force, range) of movement.

Front 35

Purkinje cells

Back 35

🔹The only output of the cerebelar cortex

🔹Always inhibitory

Front 36

Basal ganglia

Back 36

🔹Striatum, globus pallidus, subthalamic nuclei and substantia nigra.

🔹Plan and execute smooth movements

🔹Striatum communicates with thalamus by indirect (inhibitory) and direct (excitatory) pathways.

Front 37

Dopamine

Back 37

🔹Connections between striatum and substantia nigra.

🔹Inhibitory on the indirect pathway (D2 receptors)

🔹Excitatory on the direct pathway (D1 receptors)

🔹 Thus, overall excitatory.

Front 38

Lesions of the basal ganglia

Back 38

🔹Globus pallidus: inability to maintain postural stability.

🔹Subthalamic nucleus: hemibalismus.

🔹Striatum: uncontrollable movements (Huntington disease).

🔹 Substantia nigra: Parkinson (destruction is inhibitory).

Front 39

Language

Back 39

Left hemisphere damages:

Wernicke: sensory aphasia

Broca: from aphasia

Front 40

Cerebrospinal Fluid (CSF)

Back 40

Back (Definition)

Front 41

Cerebrospinal Fluid (CSF)

Back 41

Back (Definition)

Front 42

Temperature regulation

Back 42

Heat-loss: anterior hypothalamus

Heat-generation: posterior hypothalamus

IL-1 acts on anterior hypothalamus to increase prostaglandins.

Front 43

Drugs that affect Autonomic Activity

Back 43

Back (Definition)

Front 44

Chorda tympani

Back 44

CN VII: taste 2/3 anterior of the tongue

Front 45

Types of muscle fibers

Back 45

Extrafusal: alfa-motoneurons, force for contraction

Intrafusal: gama-motoneurons, adjust the sensitivity of the muscle spindle

Front 46

Muscle spindle reflexes

Back 46

Sensory information about muscle length is received by group Ia (dynamic) and group II (static) afferent fibers.

Stretching stimulates alfa-motoneurons to contract.