Nervous system part 1 Flashcards
Afferent neurons are what?
Sensory
Efferent Neurons are what?
motor
Most nervous system are organized into three divisions
Afferent, Efferent, integration
What organisms are the excepton to the three division rule?
Cnidarians
Cniarians have what type of nervous system?
Nerve net
neurons are not specialized
What is different about Cnidarians AP’s
They travel in both directions
What is different about Cnidarians neurons?
not specifically sensory or motor
but can still perform complex behavior
Cephalization occurs in most animals and is more apparent in more complex nervous systems what are two exceptions?
Cnidarians and Echinoderms
both lack cephalization
What is different about more complex organisms neurons?
they have more neurons and more synapses
What does increased synapses allow?
increases number of synapses allow for more integration of information and more complex behaviour
since memories are stored in synapses, a complex nervous system also allows for greater potential for learning
The vertebrate central nervous system:
What are some characteristics?
(4)
high degree of cephalization
unique in having a hollow dorsal nerve cord
part of the nervous system is encased within cartilage or bone (CNS-brain and spinal cord)
part of the nervous system extends to the periphery of the body (PNS nerves outside of the CNS)
Cranial and spinal nerve:
where does it exit from, how many pairs, what type of signals?
directly from skull
13 pairs
afferent and efferent signals
Spinal nerve:
Where does it branch off from?
branch from spinal cord
enter and exit between adjacent vertebrae
named based on region of vertebral column from which they emerge
What is grey mater?
neuronal cell bodies
What is white matter?
tracts of axons and their myelin sheaths
where is the white matter and grey matter located in spinal chord?
white matter on surface and grey matter inside
where is the white matter and grey matter located in cerebral cortex
grey matter on surface
white matter inside
Characteristics of Meninges?
2
connective tissue that surround brain and spinal cord
number of menings vary across taxa
Characteristics of CSF?
fills spaces within the CNS and acts as shock absorber
Characteristics of BBB
tight junctions in brain capillary endothelium astrocytes endfeet pericytes limit the passage of solutes from bloodstream into CSF protects brain from harmful substances
transporters for glucose and AA
except pineal gland, pituitary and parts of hypothalamus are permeable
What are the three main regions in the brain?
Rhombencephalon (hindbrain)
Mesencephalon (Midbrain)
Prosencephalon (forebrain)
What are the ventricals in the brain?
Cavities inside brain filled with CSF
ciliated ependymal cells, lining the ventricles circulate the CSF
What are the three regions of the Rhombencephalon ( Hidbrain )
Pons
cerebellum
medula
What does the pons do?
located rostral to medulla
pathway between medulla, cerebellum, and forebrain
controls alertness, initiates sleep and dreaming
linked to cerebellum: motor control
What is the cerebellum
two hem. at back of brain
responsible for motor coordination
contains half of the neurons in the brain!! (woah)
What are the characteristics of the Medulla?
Located at the top of spinal cord
regulates breathing, heart rate, diameter of blood vessels, blood pressure
contains pathways from spine to brain
many cross overs (L –>R)
What is the midbrains function?
Primary center for coordination and initiating reflex responses to auditory and visual information in fish and amphibians
What is the inferior colliculi?
Auditory input
What is the superior colliculi?
visual input
What changes about the midbrain in mammals?
size and function is reduced compared to amphibians
What process is the forebrain involved in?
Involved in processing and intergrating sensory info, and coordinating behavior
What are the main regions of the forebrain?
limbic system
hypothalamus
thalamus
hippocampus
cerebrum
What is the Cerebrum?
what do the left and right sides do
Outer layer in the cortex
divided into two hem.
left side- controls right side
right side- controls left side
neurons innervate the opposite side via corpus callosum
What does the hypothalamus do?
Located at base of forebrain (under thalamus)
helps maintain homeostasis (Body temp, thirst, hunger)
feeding fucking
interacts with automonic system
regulated secretion via pituitary hormones
What does the limbic system do?
network of connected structures that lie between the cortex and the rest of the brain
influences emotions, motivation, memory
What are the 5 parts that make up the limbic system?
Amygdala- aggression and fear response
hippocampus- converts short term memory to long-term memory
olfactory bulbs- smell
Nucleus accumbens- reward, addiction
Cingulate cortex- executive function of brain, decision making, motivation and planning
Characteristics of the thalamus?
Large grouping of grey matter above hypothalamus
receives input from limbic system and all senses except olfaction
relays sensory info to cortex;auditory, visual, somatosensory, visceral
major rol in regulating states of sleep and wakefulness
What are the characteristics of the cortex?
Intergrates and interprets sensory info
initiates voluntary movement
has taken over many of the midbrain functions of lower vertebrates
Contains ISOCORTEX- necessary for cognition and higher brain functions
What are Gyri?
Folds
What are sulci?
grooves
How many cortical layers?
how do the layer differ?
where are pyramidal neurons located?
what form the local connections?
6
differ in shape and density
2/3, 5, 6
interneurons
How are the cortical lobes named?
According to the function or overlying bone of the skull
