Nervous System Anatomy Flashcards
(47 cards)
1
Q
What does the Peripheral Nervous System do?
A
Connects the CNS to the rest of the body
2
Q
What NS does the Peripheral NS contain?
A
Autonomic NS and Somatic NS
3
Q
Autonomic NS
A
- AKA involuntary NS
- sends & receives messages to regulate the autonomic behaviours of the body (e.g., heart rate, respiration, digestion)
4
Q
Somatic NS
A
- Controls voluntary muscles
- Conveys sensory information to CNS
- AKA the voluntary NS
5
Q
What does NS the Autonomic NS contain?
A
Parasympathetic NS and Sympathetic NS
6
Q
Parasympathetic NS function
A
- facilitates vegetative, nonemergency response
- conserves bodily resources
- Decrease functions increased by the sympathetic NS
- Associated with rest and digestion (system becomes relaxed
7
Q
Sympathetic NS function
A
- Prepares the organs for rigorous activity
- Mobilises bodily resources
- Associated with flight or fight response (for situations that are perceived as dangerous or of high risk)
- Represses digestion and other non-essential/urgent functions to mobilise energy
- Increase HR, BP, respiration
8
Q
Anterior
A
Towards the front end
9
Q
Posterior
A
Towards the rear end
10
Q
Dorsal
A
Toward the back, away from the ventral (stomach) side, the top of the brain
11
Q
Ventral
A
Towards the stomach, away from the dorsal (back) side, underneath the brain
12
Q
Lateral
A
Toward the side, away from the midline
13
Q
What is included in the Central Nervous System?
A
Brain and Spinal Cord
14
Q
Medial
A
Toward the midline, away from the side (in the middle)
15
Q
Function of the Spinal Cord
A
- Connects the brain to the rest of the body via the peripheral NS
- Sensory nerves: bring sensory info from body to brain (entering dorsal roots)
- Motor nerves: transmit motor info from brain to body (exiting ventral roots)
- Each segment sends sensory information to the brain and receives motor commands
16
Q
What are the two types of matter in the Spinal Cord?
A
- Grey matter: located in the centre of the spinal cord, densely packed with cell bodies and dendrites
- White matter: composed mostly of myelinated axons, carries information from the grey matter to the brain or other areas of the spinal cord
17
Q
Spinal reflex
A
-Spinal reflexes occur independently of the brain
-Due to interneurons in the spinal cord
18
Q
What are interneurons?
A
Interneurons are responsible for the pre-conscious nature of reflexes
- receive sensory input
- excite motor neurons controlling muscles that withdraw the limb
19
Q
Structures included in the Brain stem
A
Hind Brain structures (Medulla, Pons, Cerebellum), the midbrain (Tectum and Tegmentum)
20
Q
Medulla structure
A
- located above the spinal cord
- Comprised of ascending & descending tracts
- small nuclei at its core is the reticular formation (an arousal system)
- consists of Cranial Nerves
21
Q
Medulla function
A
- it’s where the cardiovascular and respiratory systems link together into a united system that controls vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing
- Damage often fatal
- The effects of drugs (e.g., opiates, amphetamines) on breathing & heart rate are primarily due to their impact on the medulla
22
Q
What is the Cranial Nerves
A
- twelve pairs of nerves that enter and exit the brain directly
- Allows the medulla to control sensations from the head, muscle movements in the head, and many parasympathetic outputs
23
Q
Olfactory function (Cranial Nerve)
A
relays signals relating to smell from sensory neurons in the nose to the olfactory bulb.
24
Q
Optic function (Cranial Nerve)
A
Carries visual signals from the retina to the thalamus (for our conscious perception of vision) and to the brainstem (for vision related to our reflexes).
25
Facial function (Cranial Nerve)
- Controls the muscles needed for facial expressions, crying, salvation, and dilation of the head's blood vessel
- Relays signals relating to taste from two thirds of the tongue
26
Vagus function (Cranial Nerve)
- Relays sensory signals from the throat, and controls muscles involved in speaking, swallowing, and vomiting.
- Sensations from neck and thorax; control of throat, esophagus, and larynx parasympathetic nerves to stomach, intestines, and other organs
27
Accessory function (Cranial Nerve)
Controls shoulder and neck muscles.
28
Hypoglossal function (Cranial Nerve)
Controls muscles in the tongue.
29
What is the Pons?
- Fibre tract that lies on anterior and ventral to the medulla
- The term pons is Latin for "bridge"
- Axons from each half of the brain cross to the opposite side of the spinal cord (contralateral control)
30
Cerebellum structure
- Contains 50% of the brain's neurons, but only 10% of its volume
- Has many deep folds
31
Cerebellum function
- AKA little Brain
- Helps regulate motor movement, balance, and coordination
- Important for sensorimotor function, and critical for coordination of fine motor skills (e.g., writing, typing)
- Important for shifting attention between auditory and visual stimuli
- Greatly affected by alcohol
- People with damage to the cerebellum have trouble shifting their attention back and forth between auditory and visual stimuli
32
Mid-Brain structures
Tectum and Tegmentum
33
Describe the tectum
- Roof of the midbrain
- Composes of superior and inferior colliculi (involved in the sensory function)
34
Describe the Tegmentum
- Contains nuclei for cranial nerves and part of the reticular formation; red nucleus and substantia nigra (both involved in sensorimotor function); and the periaqueductal grey
- Sensorimotor functioning, arousal system, pain mediation
35
Structure of the Forebrain
two cerebral hemispheres
- consists of the outer cortex and subcortical regions
- outer portion is known as the “cerebral cortex”
- each side receives sensory information and controls motor movement from the opposite (contralateral) side of the body
- Structures underneath the cortex:
- Hypothalamus and Thalamus
36
Describe the Hypothalamus
- small area near the base; just below the thalamus (hypo = below)
- conveys messages to the pituitary gland to alter the release of hormones
- associated with motivated behaviours (e.g., eating, drinking, sexual behaviour)
- is essential for control of eating, drinking, temperature control, and reproductive behaviours.
37
What is the Limbic System?
- consists of a number of other interlinked structures that form a border around the brainstem
- includes the olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus of the cerebral cortex
- associated with motivated and emotional behaviour (e.g., eating, drinking, sexual activity, anxiety, & aggression)
38
Describe Thalamus
- Large two-lobed structure at top of brain stem
- relay station from the sensory organs (except smell); main source of input to the cortex
- integrates information across senses
39
Information roots from Thalamus to Cerebral Cortex
- Lateral geniculate nuclei: vision
- Medial geniculate nuclei: hearing
- Ventral posterior nuclei: touch
40
Describe the Ventricles
- Four fluid-filled cavities within the brain’s central canal containing cerebrospinal fluid
- Two lateral ventricles + 3rd ventricle and 4th ventricle
- provides “cushioning” for the brain
- reservoir of hormones and nutrition for the CNS
41
Describe the Meninges
- membranes that surround the brain and spinal cord:
- dura mater (Tough)
- arachnoid mater (spidery)
- pia mater (gentle innermost layer)
- contain pain receptors
42
Describe the Cerebral Cortex
- Consists of the cellular layers on the outer surface of the cerebral hemispheres
- Highly convoluted outer layer
- Grooves = sulci
- Bumps = gyri
- Most recently evolved, mediates most complex functions
- the longitudinal fissure separates the two cerebral hemispheres
- the hemispheres joined by two bundles of axons called the corpus callosum and the anterior commissure
- divided into four lobes
43
Occipital Lobe
- located at the posterior end of the cortex
- known as the striate cortex or the primary visual cortex
- highly responsible for visual input
- damage can result in cortical blindness
- Cortical blindness
- Apparent lack of visual function, despite functioning eyes
- e.g., the 'what is that in my external world' and the 'where is that in my external world' is to working
44
Parietal Lobe
- contains the postcentral gyrus, aka the “primary somatosensory cortex”
- primary target for touch sensations and information from muscle-stretch receptors and joint receptors
- also responsible for processing and integrating information about eye, head, and body positions from information sent from muscles and joints
- essential for spatial information as well as numerical information
- e.g., counting on your fingers
- damage can result in unilateral neglect
- One of two association cortices
45
Temporal Lobe
- located on the lateral portion of each hemisphere near the temples
- target for auditory information and essential for processing spoken language
- also responsible for complex aspects of vision, including movement and some emotional and motivational behaviours
- damage results in difficult hearing, comprehending speech, memory impairments, and emotional changes
46
Frontal Lobe
- contains the
- precentral gyrus, aka the “primary motor cortex”: responsible for the control of fine motor movement
- prefrontal cortex: the most anterior portion of the frontal lobe; an integration centre for all sensory information and other areas of the cortex
- responsible for higher functions (e.g., abstract thinking & planning)
- also responsible for our ability to remember recent events and information (“working memory”)
47
Damages to the Frontal Lobe results in
- an inability to inhibit behaviour &/or control emotion
- decreased planning and organisation
- delayed responding to stimulus events (visual or auditory)
