Flashcards in Neuroanatomy Deck (101):
What are the functions of neurones?
Proprioception. Responses to stimuli. Movement. Feeding. Senses. Balance. Blood pressure. Heart rate. Neurocrine.
What are the morphological types of neurones?
Unipolar. Pseudounipolar. Bipolar. Stellate. Pyramidal. Purkinje.
What are unipolar neurones?
Single process from soma. Ancestors of all neurons. Mainly in invertebrates.
What are pseudounipolar neurones? Give an example.
Single process split into 2. All sensory neurones. Ganglion cell of dorsal root
What are bipolar neurones? Give an example.
2 processes, one at each end. Mainly interneurones. Retinal bipolar cell.
What are multipolar neurones?
1 axon and many dendritic processes. Common in CNS.
Give an example of a stellate cell.
Motor neuron of CNS
Give an example of a Pyramidal cell.
Pyramidal cell of hippocampus.
Give an example of a Purkinje cell.
Purkinje cell of cerebellum.
What are the functions of glial cells?
Physical support. Separation. Myelination. NT scavenging. Potassium buffers in CNS. Removal of debris. Blood barrier function. Nutrition. Repair.
Which glia are responsible for nutrition?
Which glia are responsible for repair?
Where in a neuron do passive and active conduction occur?
Passive - Dendrites. Active - Axon.
What are the 3 embryological layers and their fates?
Ectoderm - Epidermis, PNS, CNS. Mesoderm - Muscles, Vascular System. Endoderm - Guts, Lungs, Liver.
Describe the process of neurulation.
Neural plate of the embryo's dorsum invaginates, forming the neural groove, by the orders of the notochord. Neural groove pinches off forming the neural tube. The remaining neural crest cells migrate and form peripheral glia.
What are the possible committed progenitors of neural crest cells?
Melanocyte. Glial. Sensory. Sympatho-adrenal. Parasympathetic. Enteric.
What are the cell fates of Sympatho-adrenal progenitors?
Chromaffin cells. Small Intestine Epithelial cells. Sympathetic neurons.
What are the cell fates of Parasympathetic progenitors?
What are the cell fates of enteric progenitors?
Peptidergic and serotonergic neurons.
What is cephalisation?
Centralisation of neural and sensory organs towards the anterior.
What are the vesicles of the 3-vesicle stage?
Proencephalon, Mesencephalon, Rhombencephalon.
What are the vesicles of the 5-vesicle stage?
Telencephalon, Diencephalon. Mesencephalon. Metencephalon, Myelencephalon.
What does the Telencephalon give rise to?
Cerebral cortex. Hippocampal formation. Basal ganglia. Amygdyla. Olfactory bulb.
What does the Diencephalon give rise to?
Thalamus. Subthalamus. Hypothalamus. Epithalamus. Optic nerve/tracts. Retinae.
What does the Mesencephalon give rise to?
What does the Metencephalon give rise to?
What does the Myelencephalon give rise to?
What does the caudal part of the neural tube give rise to?
What are the 3 flexures present in the 5-vesicle embryo?
Cephalic, Cervical and Pontine.
What is the role of the cephalic flexure?
Divides the mesencephalon and the diencephalon.
What is the role of the cervical flexure?
Separates myelencephalon from spinal cord.
What is the role of the pontine flexure?
Separates metencephalon from the myelencephalon.
What are the 8 major structures of the mature brain?
Spinal Cord. Medulla. Pons. Cerebellum. Midbrain. Thalamus. Cerebral Cortex. Corpus Callosum.
What is the Cauda Equina?
Leash of nerves above coccyx. (L2-5; S1-5).
Why does the cauda equina not reach the bottom of the spinal cord?
Bone growth is faster than neural tube growth.
What are the main sensory fibre types?
A-alpha. A-beta. A-gamma. A-delta. B. C-DR. C-sympathetic.
Describe A-alpha fibres.
Motor/Proprioception. 100ms-1. Myelinated. 15um.
Describe A-beta fibres.
Touch/Pressure. 50ms-1. Myelinated. 7um.
Describe A-gamma fibres.
Motor Spindles. 22ms-1. Myelinated. 4.5um.
Describe A-delta fibres
Pain/Temperature. 20ms-1. Myelinated. 3.5um.
Describe B fibres.
Preganglionic/Sympathetic. 8ms-1. Myelinated. 2um.
Describe C-DR fibres.
Pain. 1.5ms-1. No myelin. 0.8um.
Describe C-sympathetic fibres.
Postganglionic. 1.3ms-1. No myelin. 0.7um.
What is the relationship between spike velocity and conduction speed?
What is the relationship between absolute RP duration and conduction speed?
Describe the types of proprioceptive/touch receptors.
Merkel disk receptors - Texture/Pressure. Pacinian Corpuscle - Vibration/Pressure. Ruffini's Corpuscle - Stretch/Finger Control. Meissner's Corpuscle - Light Touch.
Describe Cold thermal nociceptors.
C fibres. <5C.
Describe Cool thermal nociceptors.
A-delta fibres. 25C.
Describe Warm thermal nociceptors.
A-delta fibres. 41C.
Describe Hot thermal nociceptors.
Where in the spinal cord do A-alpha fibres project to?
Where in the spinal cord do A-beta fibres project to?
Where in the spinal cord do A-delta fibres project to?
I and V lamina
Where in the spinal cord do C fibres project to?
What are mechanoreceptors?
Receptors which respond to mechanical slimuli e.g.: Touch, Pressure, Vibration.
Describe the properties of fast and slow adapting fibres.
Fast adapting - Stop firing quickly, start firing when stimulus removed. Slow adapting - Fire for longer.
What are algogens?
What is the role of algogens?
Cause primary hyperalgesia. Sensitisation of damaged tissue making inoccuous stimuli seem noxious.
Give examples of algogens.
Prostaglandins, Bradykinins, Serotonin, Substance P, Purines, Potassium.
What are NSAIDs?
Non Steroidal Anti Inflammatory Drugs
What is the function of NSAIDs?
Inhibition of prostaglandin synthesis by inhibition of cytosolic phospholipase A2 and Cyclooxygenase.
What are the function of Prostaglandins? Give examples.
Sensitisation of free nerve endings to mechanical/thermal stimuli - PGE2/PGI2. Excitation of subpopulations of nociceptors to evoke pain impulses - PGI2.
How is Arachidonic acid formed?
Conversion of phospholipids by Cytosolic Phospholipase A2.
How is PGG2 formed?
Arachidonic acid is converted by the Cyclooxygenase reaction of COX-1 and COX-2.
How is PGH2 formed?
PGG2 is converted by the Peroxidase reaction of COX-1 and COX-2.
What are the products of PGH2?
PGD2 (PGD synthase); PGE2 (PGE synthase); PGF2 (PGF synthase); PGI (Prostacyclin synthase); TXA2 (Thromboxane synthase).
What are the ratios of vertebrae in the spinal regions?
Cervical - 8; Thoracic - 12; Lumbar - 5; Sacral - 5; Coccygeal - 3.
At which vertebrae does the Spinal Cord end?
What are Dermatome maps?
Maps showing innervation territory of all fibres entering the spinal cord at the particular segmental level.
What comprises the Brainstem?
Pons, Cerebellum and Medulla Oblongata.
What is the function of the Spinal Cord?
Convergence of sensory and motor information. Coordination of reflexes and CPGs.
What is the function of Medulla Oblongata?
Respiration control via chemoreceptors. (Para)sympathetic control of cardiac system. Vasomotor centre BP control. Reflexes (Pharyngeal, Swallowing, Masseter).
What is the function of the Pons?
Relay of signals from Forebrain to Cerebellum. Sleep. Respiration (Pneumotaxic centre). Swallowing. Bladder control. Hearing. Eye movement. Taste. Facial expression and sensation. Posture.
What is the function of the Cerebellum?
Coordination of motor functions. Precision. Cognition (Attention/Language). Fear. Pleasure. Muscle tone.
What is the function of the Midbrain?
Vision/Hearing. Sleeping/Waking. Arousal. Alertness. Motor control. Temparature regulation.
What is the function of the Thalamus?
Relay of sensory and motor signals. Consciousness. Sleep. Alertness.
What is the function of the Corpus Callosum
What is the function of the Cerebrum?
Conscious motor movement. Sensory perception. Memory. Thought. Judgement. Learning. Habits. Olfaction. Communication
What are the 4 lobes of the Cerebrum?
Frontal. Parietal. Occipital. Temporal.
What is the function of the Frontal Lobe?
Reasoning. Movement. Emotions.
What is the function of the Parietal Lobe?
Orientation. Movement. Recognition of stimuli.
What is the function of the Occipital Lobe?
What is the function of the Temporal Lobe?
Memory. Speech. Recognition of Auditory Stimuli.
What are the layers of grey matter?
Marginal zone - Lamina I; Substantia gelatinosa - Lamina II/III; Nucleus Proprius - Lamina IV-VI; Clarke's Nucleus; Intermediolateral Nucleus; Motor Nuclei - Lamina VIII/IX.
Name 7 basal ganglia.
Hypothalamus, Subthalamic nucleus, Thalamus, Caudate nucleus, Putamen, Substantia Nigra, Globus pallidus.
What is the function of the Hypothalamus?
Secretion of trophic hormones. Body temp. Thirst/Hunger. Fatigue. Sleep. Parenting. Attachment.
What is the function of the Subthalamic nucleus?
Associated with impulsivity control. Action selection.
What is the function of the Thalamus?
Relay of motor signals to cerebral cortex. Consciousness/Alertness.
What is the function of the Caudate nucleus?
Learning/Memory. Emotion (linked to OCD). Language comprehension. Threshold potential control.
What is the function of the Putamen?
Motor skilld (movement/learning). Hate circuits.
What is the function of the Substantia Nigra?
Reward/Addiction. Movement. Dopaminergic pars compacta.
What is the function of the Globus pallidus?
Regulation of voluntary movement.
What do all basal ganglia have in common? Give an example.
All act on a subconscious level. Petting a cat requires no thought, basal ganglia ensure smooth movements.
What is the function of the anterolateral system?
What is the function of the DC-ML pathway?
Where does the anterolateral system decussate?