Week 11- Nervous System Flashcards
1
Q
The Brain
A
- Communication and control centre of the body
- Receives, processes and evaluates many kinds of input, decides on the response needed, and acts on that
2
Q
What is the brain controlled by?
A
- Involuntary activity- Autonomic Nervous System
- Voluntary- Somatic Nervous System
3
Q
What is the brain protected by?
A
- The skull
- Meninges
- Cerebrospinal fluid
4
Q
Meninges
A
- Consists of 3 continuous connective tissue membranes covering the brain and spinal cord
5
Q
Dura Mater
A
- Outer layer
- Tough, fibrous double layered membrane
- Forms the dural sinuses which collect venous blood and CSF for return to the general circulation
6
Q
Subdural Space- Lies beneath the dura
A
- Potential space
- Normally, empty but can fill with blood after an injury
7
Q
Arachnoid Mater
A
- Middle layer
- Loose, web like covering
8
Q
Subarachnoid Space
A
- Contains CSF and cerebral arteries and veins
- Lies below the arachnoid
9
Q
Pia Mater
A
- Inner layer
- Delicate, connective tissue that adheres closely to all convolutions to the surface of the brain
- Contains many small blood vessels
10
Q
Cerebrospinal Fluid (CSF)
A
- Provides a cushion for the brain and spinal cord
- Clear, almost colourless liquid
- Formed in the ventricles in the brain and flows into the subarachnoid space
- Here it circulates around the brain and spinal cord eventually returns to the venous blood
- To maintain normal pressures (ICP), it is important that equal amounts of CSF
11
Q
CSF & Arachnoid Vili
A
- Small protrusions of the through the dura mater
- They protrude into the venous sinuses of the brain, and allow CSF to exit the subarachnoid space and enter the bloodstream
- Once in the bloodstream, it is carried away and filtered by the kidneys and liver the same way other fluids are
12
Q
Blood Brain Barrier
A
- Protective mechanism provided by relatively impermeable capillaries in the brain
- Cells are tightly joined together rather than possessing pores
- This barrier limits the passage of potentially damaging materials into the brain and controls the delicate balance of electrolytes, glucose and proteins in the brain
- Lipid soluble substances can still pass through
13
Q
Cerebral Hemispheres
A
- Make up the largest portion of the brain
- 2 hemispheres separated by a fissure
- Each hemisphere is divided into 4 major lobes (frontal, parietal, occipital, temporal)
- Each has specific functions
- Each hemisphere is concerned with voluntary movement and sensory function in the opposite side of the body
14
Q
What are the 2 areas involved in language
A
- Broca’s area
- Wernicke’s area
15
Q
Broca’s Area
A
- Motor or expressive speech area
- Controls the output of words, both verbal and written and ensures they are coordinated in an appropriate and understandable way
- Located at the base of the left frontal lobe
16
Q
Wernicke’s Area
A
- Integration centre that comprehends language received, both written and spoken
- Located in the posterior temporal lobe
- Has connective fibres to the visual and auditory areas
17
Q
Limbic System
A
- In cerebral hemispheres
- Not a separate system but a collection of structures
- Responsible for emotional reactions and feelings
- Has many connections to all areas of the brain
- Linked to the hypothalamus- responsible for the autonomic responses associated with emotions (altered BP, nausea, etc)
18
Q
Diencephalon
A
- Central portion of the brain
- Contains the thalamus and hypothalamus
19
Q
Thalamus
A
- Main nerve bodies that serve as a sorting and relay station for incoming sensory impulses
20
Q
Hypothalamus
A
- Key role in maintaining homeostasis in the body
- Regulation of body temp, intake of food and fluid and the regulation of sleep cycles
- Regulations of libido
21
Q
Brainstem
A
- Connects the brain to the spinal cord
- Contains: Pads, Medulla Oblongata, RAS
22
Q
Pons
A
- Contains afferent (incoming) and efferent (outgoing) fibers
23
Q
Medulla Oblongata
A
- Vital control centre that regulate respiratory and cardiovascular function
24
Q
RAS (Reticular Activating System)
A
- Determines the degree or awareness of the cerebral cortex (decides which of the incoming sensory impulses the brain ignores and which it notices)
25
Q
Cerebellum
A
- Lies dorsal to pons and medulla, below the occipital lobe
- Function to coordinate movement and maintain posture and equilibrium
- Takes impulses from visual pathways, vestibular pathways (inner ear), propioceptors in joints and muscles
26
Q
Blood Supply to the Brain
A
- Supplied by the internal carotid arteries and vertebral arteries
- Each internal carotid is a branch of the left and right common carotid
- Vertebral arteries branch off the subclavian arteries
- Each of these artery’s branch to form smaller arteries that provide the blood supply to the entire brain
- Once deoxygenated, venous blood from the brain collects in the dural sinuses and then drains into the right and left jugular veins to be returned to the heart
27
Q
Circle of Willis
A
- Structure located inside the head that supplies blood to the brain
- Ensures blood flow remains unimpeded in case any of the principal supplies are damaged
- This means if one of the vessels supplying blood to the brain is blocked or narrowed, the other vessels can preserve cerebral perfusion to prevent ischemia
28
Q
How many cranial nerves do we have?
A
- 12 Pairs
29
Q
Where do the cranial nerves originate from?
A
- Originate from the brainstem and pass into the skull to serve structures in the head and neck
- May consist of motor fibres only or sensor fibres, or a mix of both
30
Q
Oh, Oh, Oh To Touch And Feel A Girls Vagina, So Hot
A
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Spinal accessory
Hypoglossal
31
Q
Olfactory
A
- Sensory, smell
32
Q
Optic
A
- Sensory, vision
33
Q
Oculomotor
A
- Motor, eye movements including eyelids
34
Q
Trochlear
A
- Motor, eye movements
35
Q
Trigeminal
A
- Sensory/ motor, general sensory- eye, nose, face, or oral cavity, teeth
- Speech muscles
36
Q
Abducens
A
- Motor, eye movements
37
Q
Facial
A
- Sensory/ motor, taste, muscles of facial expression, scalp muscles
38
Q
Vestibuculocochlear
A
- sensory/ motor, taste, gag reflex
39
Q
Vagus
A
- Sensory/ motor, external ear, parts of taste, heart and lungs smooth muscle, glands of GI system, diaphragm
40
Q
Spinal Accessory
A
- Motor, voluntary muscle of pharynx, head movements
41
Q
Hypoglossal
A
- Motor, muscles of the tongue
42
Q
Spinal Cord
A
- Protected by the bony vertebral column, meniges and CSF
- Starts at the medulla oblongata and ends at the level of the 1st lumbar vertebrae
- Past thus, there is a bundle of nerve roots known as the Cauda Equina
- Consists of nerves that innervate the skeletal muscles
- Ascending and descending tracts
43
Q
Ascending and Descending Tracts
A
- Ascending relay information from the skeletal muscles to the brain
- Descending from the brain to the muscles for movement
44
Q
Spinal Nerves
A
- 31 pairs located in the spinal column
- Carry motor and sensory fibres to and from the organs and tissues
- Innervate at the skin level- called dermatomes
45
Q
Reflexes
A
- Automatic, rapid, involuntary responses to a stimulus
- Involves a stimulus from a receptor that is conducted along an afferent nerve fibre, tells the brain, send an efferent stimulus back to the peripheral nerve to elicit a response
- Can also have acquired reflexes (salivation with smell of food)
46
Q
Neurons
A
- Highly specialized cells that conduct impulses throughout the CNS and PNS
- Require glucose and O2 for metabolism
- Structure can vary depending on its function
- They all have: dendrite, cell body, axon, covered in myelin sheath, nodes of ranvier
47
Q
Dendrite
A
- Receptor site, conducts the impulse towards the cell body
48
Q
Cell Body
A
- Contains the nucleus
49
Q
Axon
A
- Conducts impulses away from the cell body towards the effector site or connecting neuron
50
Q
Covered in myelin sheath
A
- Insulates the fibre and speeds up the rate of conduction
51
Q
Nodes of Ranvier
A
- Spaces between the myelin sheath
52
Q
Impulse Transmission
A
- Impulses are transmitted from cell to cell via chemical neurotransmitters
- Involves the presynaptic and postsynaptic synapses
- Axon and receptor are separated by a synaptic cleft- filled with fluid
- In order for impulses to travel along, the released chemical flows across the cleft to the receiving receptor (Receptors are specific for each type of chemical)
53
Q
What are the different types of neurotransmitters?
A
- Acetylcholine
- Norepi/ Epinephrine
- Dopamine
- Serotonin
54
Q
Acetylcholine
A
- Chief neurotransmitters in the PNS
55
Q
Norepi/ Epinephrine
A
- Neurotransmitters in the SNS
- Causes vasoconstriction and increase in HR
- Stimulates alpha and beta receptors
56
Q
Dopamine
A
- Released when your body is expecting a reward
- Cycle of motivation, reward, reinforcement
57
Q
Serotonin
A
- Mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation, and some social behaviour
58
Q
Autonomic Nervous System
A
- Acts as the involuntary control
- Incorporates the SNS and PNS (typically have antagonistic effects, key in maintaining homeostasis)
- SNS & PNS
59
Q
Sympathetic Nervous System
A
- Increases the level of activity including cardio, resp and neuro functions
- Fight or flight, stress
- Involve release of Ach, epi, and norepi
60
Q
Parasympathetic Nervous System
A
- Dominates the digestive system and aids in the recovery after the sympathetic stimulation
- Responsible for slowing RR, HR, constriction of pupils
- Largely innervated by the vagus nerve
- Active chemical neurotransmitter is Ach as well
