Physiology Flashcards
WWhat is the most common neuron type to be found in the central nervous system?
Multipolar neuron
Where are bipolar neurons located?
Only found in the eye, ear and nose.
WHat is the normal time for synaptic delay?
0.5 seconds
What are the different types of Synapses?
Axodendritic- Between axons terminals of one neuron and dendrites of another.
Axosomatic - between axons and neuronal cell bodies
Axoaxonic
Dendrodendritic
Dendrosomatic
What is the most common type of Synapse?
Axodendritic
True or False? Amines are stored in small clear vesicles while Amino acids are stored in small dense vesicles.
FALSE!! Amines are stored in small DENSE vesicles.
Amino acids are stored in small CLEAR vesicles.
What are examples of excitatory amino acids?
Glutamate, Aspartate
What are examples of inhibitory amino acids?
Glycine, GABA
What are examples of Amines?
Dopamine, Norepinephrine, epinephrine, serotonin, histamine.
Which neurotransmitter is stored in large dense vesicles?
Neuropeptides
What are examples of Neuropeptides?
- Substance P, Vasopressin, endorphins, neurotensins etc.
- Purines and Pyrimidine
Adenosine, ATP, UTP (Uridine triphosphate)
Where are neuropeptides synthesized?
They are synthesised by ribosomes in neuronal cell bodies?
Why are neurotransmitters stored in vesicles?
- Concentration- (mediated by binding proteins and by H+ powered vesicular transporters)
- Protection from degradation - by proteases and esterases
- Allows for regulation
- Provides a storage system
Fill in the blanks.” ________ is needed for synaptic vesicle budding ,fusion and discharge .”
Ca 2+
What is the name of the substance that is used to coat the vesicular membrane , after neurotransmitter release?
Clathrin
How is Calcium restored to its resting level during vesicle transport?
By a Ca2+-Na+ antiport
Which neurotoxin is known to destroy synaptic vesicles?
Batrachotoxin
Botulum toxins damages which proteins?
t-SNARES and v-SNARES
Fill in the blanks. “ VAMP1 and VAMP2 proteins known as ____________are expressed in brain and are constituents of the synaptic vesicles, where they participate in _____________.”
Synaptobrevins
They participate in neuromediator release.
Which Vesicle associated membrane protein participates in regulated and constitutive exocytosis ?
VAMP3 (known as CELLUBREVIN)
True or False? VAMP 8 is involved in the the transport from the Golgi apparatus?
FALSE! VAMP4 is involved in transport from the Golgi
Fill in the blanks. “_________and __________ participate in constitutive exocytosis
VAMP5 & VAMP 7 (SYLB1)
True or False? VAMP5 is a constituent of secretory vesicles, myotubes and tubulovesicular structures while VAMP7 is found both in secretory granules and endosomes.
TRUE!!
Which VAMP is also known as Endobrevin ?
VAMP 8
Which VAMP participates in endocytosis and is found in early endosomes?
VAMP 8
Which VAMP also participates the regulated exocytosis in pancreatic acinar cells?
VAMP 8
Fill in the blanks. “ In hypoxia Cortical areas are more sensitive to __________-than the vegetative centers of the brain stem.”
Hypogylcemia
True or False? The brain depends more on aerobic metabolism.
TRUE!!
How does Glucose enter the brain?
Glucose enters the brain via GLUT 1 in cerebral capillaries ( cerebral arteries).
Where is Glycogen normally stored in the brain?
In astrocytes
Fill in the blanks. “During prolonged starvation, ____________ and _____________ replaces glucose as the predominant fuel for brain metabolism. “
Beta-hydroxybutyrate & Acetoacetate
Which Glucose transporter transport glucose from interstitium into neurons and glial cells?
GLUT3 / GLUT5
What area in the brain is the glucose sensor?
Ventromedial Hypothalamus
At that level of glucose is Epinephrine triggered?
At ~70 mg/dL of blood glucose.
What are the symptoms of Hypoglycaemia ?
Shakiness, trembling, nervousness, and tachycardia.
What are the Multiorgan effects of Hypoglycaemia ?
(1) drives glycogenolysis,
(2) stimulates gluconeogenesis in the liver and kidney,
(3) decreases peripheral glucose uptake,
(4) stimulation of lipolysis.
In type 1 or 2 diabetes, what becomes the critical counterregulatory factor?
Epinephrine secretion
When is Cortisol & Growth hormone released in response to hypoglycaemia?
After 3 hours
What are the functions of Cortisol & Growth hormone?
(1) systemic glucose production.
(2) suppressing peripheral glucose oxidation and use.
(3) lipolysis.
How are ketone bodies transferred into the brain?
Through the blood-brain barrier monocarboxylic transporters (MCTs)
What are the enzymes involved in oxidizing ketone bodies to acetyl coA?
- 3-hydroxybutyrate dehydrogenase
- SCOT (succinyl-CoA-acetoacetate-CoA transferase)
- Mitochondrial acetyl-CoA thiolase
Filll in the blanks.” ___________ is a non-enzymatic byproduct of ketone body synthesis and is largely excreted in the urine or exhaled from the lungs.”
Acetone
True or False? The amount of acetyl-CoA formed from ketone body metabolism is greater than that formed from glucose metabolism.
TRUE!!
What are the results of excessive Glutamate release?
- Epilepsy, traumatic brain injury
- Na+ and Ca2+ IC accumulation leading to swelling
Fill in the blanks. “ Glutamate entering the brain takes up ammonia and leaves as ________.”
Glutamine
What substance is believed to be a major cause of the bizarre neurologic symptoms in hepatic coma?
Ammonia
Where is Glutamine metabolised in the body?
In the liver/kidneys
What structures form the Circle of Willis?
2 Internal carotid and 2 vertebral arteries
True or False? A drop in Cerebral Perfusion Pressure (CPP) produces vasodilatation
A rise in CPP produce vasoconstriction.
TRUE!!
What is a Haemorrhagic stroke?
Rupture of aneurysm, road traffic accident and rupture of cerebral artery.
What is an Ischaemic stroke?
Thrombus formation on atherosclerotic plaque, blockage by emboli. Reduced glutamate uptake by astrocytes, and the increase in local glutamate causes excitotoxic damage and death to neurons.
Cerebrospinal fluid is secreted by?
Choroid plexuses
What is the total CSF in the brain?
120 -150ml
How much CSF is produced per minute and per day?
0.5ml per minute & 550-720 ml per day
What is the compound that’s contain in CSF the most?
Na + ( 154mM)
Fill in the blanks. “ The CSF passes back into blood through tiny diverticula of arachnoid mater called _____________, which project into the venous sinuses.”
Arachnoid villi (arachnoid granulations)
True or False? CSF Removes metabolic wastes through absorption &
Transports hormones.
TRUE!!
What are senses that do NOT reach to consciousness?
Muscle length
Muscle tension
Arterial blood pressure
Central venous pressure
Inflation of lungs
Temperature of blood in head
Arterial Po2,
What are special senses?
Vision, Smell, hearing, rotational and linear acceleration and taste.
What are general senses?
Touch, pressure, cold, warmth, pain, Joint position and movement.
Where are Merkel’s discs located ?
In the basal layer of the epidermis
What are the senses that DO NOT reach to consciousness?
Muscle length, muscle tension, arterial blood pressure, central venous pressure, inflation of lungs, temperature of blood in head, arterial Po2,
Which classification of sensory receptors monitor the degree of Stretch?
Proprioceptors
Where are Proprioceptors located?
In musculoskeletal organs
What are the Classification of Sensory receptors by location?
Exteroreceptors
Interoreceptors
Propriorecptors
What are the Classification of Sensory receptors by Modality?
- Mechanoreceptors – respond to mechanical forces.
- Thermoreceptors – respond to temperature changes.
- Chemoreceptors – respond to chemicals in solution.
- Photoreceptors – respond to light – located in the eye .
- Nociceptors – respond to harmful stimuli that result in pain
What are the classification of receptors according to their structure?
Free nerve endings
Encapsulated nerve endings
Where are Merkel discs located?
In the Basal layer of the epidermis
What are examples of Free nerve endings?
- Free nerve endings of sensory neurons
- Merkel dics
- Hair follicle receptors
What are examples of Encapsulated nerve endings?
Meissner’s corpuscles
Paninian corpuscle
Ruffin’s corpuscles
True or False? Merck’s discs are slow- adapting & sensitive to touch and vibration.
TRUE !!
Fill in the blanks. “ Krause end bulbs are _________.”
Thermoreceptors
Fill in the blanks. “ ____________is rapid acting, Sensitive to light touch & vibrations and has a superficial location?”
Meissner’s corpuscles
Fill in the blanks. “ ______________ are Sensitive to deep pressure & vibrations
Rapid adapting
Deep subcutaneous tissue location.”
Pacinian corpuscles
What is the name give to the sensory nerve endings within the joint capsule?
Joint kinesthetic receptors
What measures the changing length of a muscle?
Muscle spindles
What is the Receptive area of a sensory unit?
The ‘receptive field’ of a sensory unit is the area, from which a stimulus produces response in the unit.
True or False?The area of sensory cortex devoted to a body region is relative to the number of sensory receptors.
TRUE!!
True or False? Chemoreceptors have Ligand gated channels .
TRUE!!
Fill in the blanks. “__________ alters the permeability of the membrane while _____________changes the receptor membrane characteristics.
Temperature change - alters the permeability of the membrane.
Electromagnetic radiation - changes the receptor membrane characteristics.
What is a Tonic receptor?
A tonic receptor is a sensory receptor that adapts slowly to a stimulus. In this way it conveys information about the duration of the stimulus.
What are examples of Tonic receptors?
Pain receptors, Joint capsule and Muscle spindle
What is a Phasic receptor ?
A phasic receptorA phasic receptor is a sensory receptor that adapts rapidly to a stimulus. The response of the cell diminishes very quickly and then stops
What are examples of Phasic receptors?
Pacinian corpuscle.
What are the neurotransmitter & stimuli of Large myelinated Aβ fibers?
Mechanical stimuli - Glutamate
What are the stimuli and the neurotransmitter for Small Myelinated Aδ fibers
for?
Cold receptors & Nociceptors that mediate fast pain
&
Substance P
True or False? The dorsal horn includes Laminae I-VI.
TRUE!!
Which lamina is known as the Intermediate zone?
Lamina VII ( 7)
Which laminae of the spinal cord is known as the Ventral zone?
Lamina VIII (8) - IX (9)
Fill in the blanks. “ Lamina I is known as ________.”
Marginal zone
Fill in the blanks .” Lamina II is known as _________.”
Substantia gelatinosa
True or False? The substantial gelatinous receives afferent information from myelinated fibres.
FALSE!! The substantia gelatinous recipes afferent from Non-myelinated fibres
Fill in the blanks.” Lamina II, IV, & VI is knowns as the ____________.”
Nucleus Proprious
What is the function of the Clarke’s nucleus?
Cells of Clarke’s nucleus relay information about the position and movement of the leg and lower trunk directly to the cerebellum
