Chapter 1: Nervous System Organization Flashcards
Adaptive Trait
a characteristic that increases the chances of survival and reproduction.
What happens to the frequency of an adaptive trait?
the adaptive trait will be selected for and will thus become more common in the population. A change in gene frequency that codes for the adaptation will increase
natural selection is a ____ that leads to the improvements of organismal design.
natural selection is a process
why may the end product of evolution still not be optimal?
because an adaptation must strike a balance between optimal design and energy cost.
Example of how biological structures reflect design principles
biological structures follow physical laws.
ex/ vertebrate eyes follows the laws of optics. The anableb for example spends its time on the water surface, peeking out of the water and looking down into the water at the same time. They only have 2 corneas and retinas, like humans, but each cornea and retina is divided into top and bottom halfs in an OVOID shape in order to follow SNELLS LAW
- the lens is more curved where it passes light coming though the water, nad less curved light passes coming through air in order to compensate for the differences of refractory index of air and water.
Neuron noisiness
represents a compromise between the need for communication between neurons and the need to conserve energy; the neurons cannot be completely “noise-proof” because that requires the synthesis (energy costly) of myelin to extreme degrees
CNS
brain and spinal cord
any nervous tissue outside the brain and spinal cord belongs to:
the PNS
ganglia
distinct clusters of neurons that typically form a bundle in the PNS
the PNS is divided into the ___ and ___ Nervous systems
autonomic and somatic nervous systems
example of an autonomic nervous system
the enteric nervous system; part of the autonomic nervous system that lies in the gut and plays a crucial role in digestion.
the CNS neurons are highly centralized by___-
accumulating in the brain
benefit of centralization and cephalization
centralization makes communication faster and more efficient because APS do not need to be propagated as long of a distance. This is more METABOLICALLY COST EFFECTIVE for the cell
grey matter and white matter
grey matter: cell body, dendrides, unmyelinated neurons
white matter: myelinated axons.
Fiber Tract
“the ganglia of the CNS”: long axon bundles in the CNS
T/F: all lobes in the brain are the same size regardless if one feature is more important than the other
false. there are different amounts of brain regions dedicated to each part function depending on importance of use.
CNS neurons are clustered into specific brain regions of ____ matter , separated by large ____ (white matter)
CNS neurons are clustered into specific brain regions of GREY matter , separated by large FIBER TRACTS(white matter)
brain nuclei
clusters of cell bodies that execute a similar function and segregate themselves from other cell bodies with different features.
On a HUMAN: Label the dorsal ventral inferior and superior sides
dorsal: back
superior: top of head
inferior: bum
ventral: belly
posterior and anterior sides in humans correspond to ___- and _____ sides
posterior: dorsal
anterior: ventral
anterior portion of the brain
aka the ventral side of the brain because it is on the same side as a persons belly
posterior portion of the brain
aka the dorsal side of the brain because it is on the same side as a persons back
in non humans, where is the dorsal ventral rostral and caudal sides?
on an animal that walks on all fours:
dorsal: spine
ventral: underbelly
rostral: tip of snout
caudal: tail.
medial
towards an organisms midline. Plane that bisects the brain into left and right hemispheres
when you cut a brain at the midsaggital plane, where was the cut made? What’re you looking at?
the cut was made at the midline. you would be seeing the entire half of the brain from the side
lateral
away from the midline. towards the right or left.
coronal plane view
cutting the brain in half, separating the anterior and posterior sides. you would see the “front view”
a coronal plane view is aka__
a cross section or transverse view
horizontal plane
cutting the brain opposite of sagital (separating the superior and inferior portions)
ipsilateral
on the same side when referring to 2 different structures
contrallateral
on opposite sides when referring to 2 different structures.
Nissl stain
stains the endoplasmic reticulum, allowing the visualization of cell bodies
Myelinated axons appear ____ when staining brain cells
dark blue typically
names for adult structures is based on the ____ nature of brain development
hierarchical nature of brain development.
in early development, brain is divided into __ ___ and ____
hind, mid, and forebrain.
the thalamic and hypothalamic nuceli aggregates are located in the ___brain
forebrain
rhombencephalon
hindbrain
3 main structures of the hindbrain
medulla, cerebellum and pons
function of the pons
connects the cerebellum to various other brain structures
mesencephalon
mid brain
2 main divisions of the midbrain
1: colliculus: superior and inferior
2: tegmentum
superior vs inferior colliculus
superior involved in processing visual info
inferior involved in processing auditory info
the midbrain and hindbrain are often combined togetehr to form the __
brain stem
3 primary structures of the brain stem
medulla, pons and tegmentum
prosencephalon and its 3 main components
forebrain, broken down into 3 parts:
diencephalon: thalamus and hypothalamus
telencephalon: striatum and pallidum
cerebral cortex: typical “brain” broken into 4-5 lobes
T/F: cerebral cortex is segregated into brain nuclei
false. unlike the brain stem and the di and telencephalon portions of the forebrain, the cerebral cortex is separated by layers, aka LAMINAE
how many layers are typically in the cortex? Where could you find structures that are not as layered? Name “thinner” cortical structures
there are usually 6 layers of cortex.
you can find structures that are 2-3 layers in the most medial and most lateral portions of the brain.
Examples include the hippocampus and piriform cortex.
the piriform cortex is more ___ than the hippocampus
more anterior than the hippocampus. If you are looking for the piriform cortex, you must look to region “closer to the face”