Labs Flashcards
What is the Powerlab?
Recording hardware that measures electrical signals via different biological transducers.
Can measure finger pulse, blood pressure, respiration and electromyography.
What is LabTutor and LabChart?
Computer software packages that control the Powerlab and display the measured electrical signals.
How do you calculate BMI?
Weight divided by height (squared).
What is the test used for measuring fat distribution?
Calculating the waist:hip ratio which is waist circumference divided by hip circumference.
Women: Below 0.8.
Men: Below 0.95.
How can skeletal size be determined?
Measuring the circumference/diameter of a part of the body that is non-muscular and not a usual fat deposition site.
Elbow width is commonly used.
What is the lean body mass?
The non-fat proportion of the body.
How can lean body mass be estimated?
Measuring the body density using skinfold thickness measurements.
Calipers (exert a constant pressure at the jaws) measure the depth of dermal adipose tissue which whole body measurements can then be extrapolated from.
What are the layers found in the cerebral cortex?
Layer I: Molecular layer. Layer II: External granular layer. Layer III: External pyramidal layer. Layer IV: Internal granular layer. Layer V: Internal pyramidal layer. Layer VI: Fusiform layer.
What is the difference between agranular and dysgranular?
Agranular describes cortical areas with no layer IV whereas dysgranular describes cortical areas with a rudimentary layer IV.
What are the supporting cells to neurons?
Glia cells.
Describe the cellular composition of a neuron.
Soma (cell body) with associated processes (dendrites and axons).
Dendrites radiate out for up to 1mm and are specialised for receiving nerve connections. Some have protuberances which are specialised for receiving connections from other neurons via synapses.
Axons conduct nerve impulses away from the soma for up to 1m. These generally do not taper like dendrites.
Give 3 methods for staining neurons and their uses.
Nissl Stain: stains soma but not processes. Used to study distribution of somata in certain brain regions.
Fibre Stain: stains processes. Used to study complexity of neuropil.
Golgi Stain: randomly stains whole nerve cells for reasons unknown. Used to study and visualise whole individual nerve cells.
OTHER METHODS: Electron Microscopy. Histochemical/Immunohistochemical methods. Receptor Autoradiography. Neuroanatomical Tracing Methods.
Define cytoarchitectonics.
The subdivision of CNS structures based on the organisation and distribution of neuronal somata within them.
Define myeloarchitecture.
The distribution of fibre tracts in the brain.
What makes up the white matter?
Myelinated axons.
What makes up the grey matter?
Nerve cell bodies.
What is the corpus callosum?
Thick region of white matter under the cortex that connects the left and right cerebral hemispheres.
What separates the left and right cerebral hemispheres?
The longitudinal fissure.
What is lateralisation of brain function?
The tendency for some neural functions or cognitive processes to be more dominant in one hemisphere than the other.
What are gyrus and sulcus in neuroanatomy?
Gyrus is the ridge and sulcus are the depressions which increase the surface area of the cerebral cortex. Confined to skull limiting brain size.
What is the approximate volume and weight of the human brain?
1-1.5l and 3 pounds.
Why does a human brain in situ have a different volume to preserved brain?
Lost matter from Alzheimer’s/gained from a tumour.
Brain has lost it’s blood supply.
Preserved brain denser because lost CSF cushioning and shrinks with fixatives.
What is the cerebellum?
Hindbrain structure which coordinates movement, balance and learning of complex motor skills.
What is the Purkinje cell layer?
Layer of large neuron cell bodies located at the interface of molecular and granular layers.
What is the shape of the Purkinje cell processes?
Spiky zig zag shaped like a spider’s web forming out like a tree into the molecular layer.
What is stereology?
3D interpretation of 2D cross sections of materials or tissues.
What conditions are associated with extensive damage to the hippocampus?
Amnesic states and dementia.
What does Toluidine Blue stain?
Cell nuclei.
What does the Weigert-Pal procedure stain?
Myelin.
What is neuronal migration?
Brings cells into appropriate spatial relationships with each other. Final mitosis is in the ventricular zone; CNS neurons migrate within the neural tube but PNS migrate longer distances from the neural crest.
2 methods: (1) Guided by specialised adhesion molecules in extracellular matrix/cell surface. (2) Crawl along radial glia (cerebrum, hippocampus etc).
What cells produce myelin in the CNS and PNS?
CNS: Oligodendrocytes.
PNS: Schwann Cells.
What is the neocortex?
Most recently evolved area of the brain concerned with higher brain functions. Different to emotional centre in limbic brain and basic life functions in the dinosaur brain.
What is the name of neurons which project axons over a long distance?
Golgi type 1. (Golgi type 2 are short/no axons).
What are interneurons?
Involved in communication of sensory/motor neurons and CNS.
What is the neurotransmitter used at a neuromuscular junction?
AcH broken down by acetylcholinesterase.
What structures are found at the growing tip of neuronal processes?
Growth cone with filopodia and lamellipodium.
What is the shape of an astrocyte? Give some possible functions.
Star shaped.
(1) Spatial buffering.
(2) Metabolic support.
(3) Guidance during migration.
What is the function of glial cells and give some types.
Surround neurons providing support and insulation.
Oligodendrocytes and Schwann cells - insulate.
Astrocytes - BBB, provide nutrients, maintenance of ion concs and repair after trauma.
Ependymal cells - Line CSF filled ventricles and central canal of spinal cord.
Microglia - Macrophages of brain.
Satellite cells - Similar to astrocytes plus cushioning effect.
What is a Langendorff preparation?
An isolated perfused mammalian heart useful for teaching physiology and pharmacology.
What stimulates the contractions of the heart?
Action of the sinoatrial node (pacemaker)
What are the affects of the sympathetic nervous system on the heart?
Noradrenaline/Norepinephrine at postsynaptic beta 1 adrenoreceptors increase the force and rate of the heart.
What are the affects of the parasympathetic nervous system on the heart?
Acetylcholine at M2 muscarinic receptors decrease the force and rate of the heart.
What drugs affect the neurotransmitters of the sympathetic and parasympathetic nervous systems in terms of heart control?
Propanolol blocks beta 1 adrenoreceptor.
Neostigmine inhibits cholinesterase.
Atropine blocks M2 receptor.
