Lecture 2 Flashcards
What makes a species?
Group isolated reproductively from other organisms (geographically, historically, behaviourally - courtship rituals)
Branching off when barrier separates subpopulations
- evolve independently until impossible to cross-fertilize
What is the evoltution of vertebrates?
Chordates - dorsal nerve cords Vertebrates -bone protecting nerves (Had neural tubes, have simple nervous systems)
What does primate mean?
Primus "first" "foremost" No single characteristic possessed by all 16 families -old world monkeys -hominid Apes are closest human living relative (chimps share 99% human genome) Homo, evolved from Australopithecus (8 species; 1=living homo sapient.) -many coexisted and inter-mated - homo sapient a combination of homo species Large brain cavity; largest homo species Used fire and tools Walked up right Modern humans (40K ya) -art writing agriculture ranching
How is the evolution of the brain and behaviour understood?
Constantly tinkering, not following a blueprint of some perfect design
-changes based off environmental context
-Rapid changes by advantageous mutation and or changes in environment
Exaptations are evolved functions that were coopted to serve additional functions
-High level motor sequencing - language
Similar traits are not always from the same origin. What is the difference between analogous and homologous?
Analogous - results from convergent evolution. (similar solution to same environmental problems (fins))
Homologous - from the same origin (sleep cycles)
What does the evolution of the brain look like?
Brain size does not = IQ
Relative brain size does not = IQ
Relative cerebrum to brain stem = best prediction of intelligence
(Increase in cerebrum size and convolutions (surface area))
Brain homologous in anatomy, structure, connectivity, function in related species
What is epigenetic?
The study of all mechanisms of inheritance other than the genetic code and its expression
Regulation of gene expression by environment
Only 1% of DNA is genes
Other 995 is regulatory coding like non coding RNA (regulates RNA expression)
Gene - environment regulate methylation and histone acetylation (exercise/diet, can be trans-generational (stress))
What is Methylation?
Is the reaction that occurs when a methyl group attaches to a DNA molecule
Reduce the expression of genes
What is histone
The reaction that occurs when a histone changes their shape and in so doing influences the shape of the adjacent DNA
Either decrease or increase gene expression
What does RNA do?
It translates the genetic code as it proceeds. It regulates whether to not genes are expressed
What is epigenetic in twin studies?
Epigenetic changes are a byproduct of experience and not genetics
Similar in early life and diverge with age
(depending on tissue type, monozygotic twins are not genetically identical - disease discordant monozygotic twins)
-See disease states that are different between them because of epigenetic
One is an alcoholic and the other isn’t because it is experience driven.
What are the 2 divisions of the nervous system?
Central nervous system (brain and spinal cord)
Peripheral nervous system ( nerves located outside the brain and spinal cord (motor and sensory))
What are is under the autonomic division of the peripheral nervous system?
Involuntary
Afferent nerves (info on state of organs, sensory)
Sympathetic and parasympathetic nervous system (oppose each other , fight/flight vs rest/digest - mobilize or store energy, indicative of arousal state
efferent nerves)
What is under the Somatic divisions of the peripheral nervous system?
Voluntary
Afferent nerves: bring info into the CNS A= approach
Efferent nerves: carry info out of CNS (motor) E= exit
What are anatomical difference in the sympathetic?
Come from different regions of the CNS
-Sympathetic - from the thoracolumbar region
Differing locations of ganlgia
- Sympathetic - close to spinal cord
Differing lengths of postganglionic fibres
- long
Postganglionic branching
-Lots, so that multiple organs can be mobilized at once
What is the anatomical difference in the parasympathetic?
Come from different regions of the CN -Parasympathetic - from the craniosacral region Differing locations of ganlgia -close to target organs Differing lengths of postganglionic fibres - short Postganglionic branching -very little branching
What are cranial nerves?
There are 12 pairs of nerves in periphery that originate on ventral surface of brain instead of spinal cord.
Purely sensory; olfactory and optic
Rest are autonomic, motor and sensory
Not part of the brain or spinal cord
How is the CNS protected?
3 layers of meninges -Dura -Arachnoid membrane -(subarachnoid space) -Pia Cerebralspinal fluid (cushions) Encased in bone
What are the three layers of the meninges?
Dura mater - hard outer layer - restrict movement within skill -sinus (drain deoxyblood and CSF waste) Arachnoid mater (web like) - subarachnoid space (CSF, large blood vessels) Pia mater -adheres to surface of the CNS -enclose CSF
