Nervous system Flashcards
CNS=
brain & spinal cord
PNS=
involves cranial nerves & spinal cord.
Ganglia =
part of PNS. They collect neuronal cell bodies e.g., DRG
What are the two functional divisions of the CNS=
somatic nervous system- voluntary
autonomic nervous system- involuntary
- So, somatic sensory pathways sends info to CNS. CNS then sends somatic/ automatic pathways to specific areas of body.
Sensory Vs motor pathways
sensory= afferent
motor= efferent
Meninges of brain=
membranes that protect the brain and allow CSF to move around tissues
What are the layers of the meninges
- dura mater
- arachidonic mater
- pia mater
Subarachnoid space
between the arachnid mater and Pia mater, it consists of CSF.
CSF=
is produced in ventricles of the brain, mainly in the choroid plexus,:
- lateral ventricles
- 3rd ventricle
- 4th ventricle- then CSF flows into subarchanoid space
- choroid plexus of lateral ventricle
Functions of CSF=
- Protective medium for brain i.e., cushioning/ trauma
- nutritive e.g., glucose
- removes metabolites e.g., urea, lactate
- provides stable ionic environment e.g., Na+, K+
Gyri=
ridges of brain
Sulci=
are between the gyris
Grey matter=
contains nerve cell bodies, neurons, glial cells, blood vessels and have no long fibre tracts
White matter=
have fibre tracts, connects different areas of the brain. Have sensory and motor pathways that are ascending/ descending.
Some key fibre pathways of white matter:
- Corpus collosum
- Internal capsule
- Association fibres
Frontal lobe=
Planning, emotion, mood, behaviour, motor function, smell
Temporal=
hearing, language, memory
Parietal lobe=
touch, pain, temperature, sensation,
Occipital=
vision
cerebellum=
- controls balance/ coordination
- Influences posture and muscle tone
- ‘motor learning’
Brain stem=
Autonomic control of body systems. Main sensory/ motor pathways pass through
Consists of medulla, pons and midbrain
Contains ascending and descending nerve tracts
Origin of cranial nerves
Contains reticular formation:
- Filtering
- Control of sleep and consciousness
- Modulation of pain
- Regulation of cardiovascular and respiratory systems
- Somatic motor control
- Gaze centres
Insula of brain=
thin grey matter tissue separating temporal lobe from inferior parietal cortex.
Functions: conscious awareness, emotional processing, homeostatic error detection, gustation & audio-visual integration
Somatic motor cortex =
Motor control of skeletal muscle & motor planning
Brocas area=
- Motor control of speech
- Speech planning (stutter)
- Motor planning
- Language output area
- ability to speak wrords
Wernicks area=
- language
- reading/ listening
- recognition of listening
- association with meanings
- context
- ability to understand the words
What are the functions of the cerebellum?
- Control of balance
- Influences of posture and muscle tone
- Coordination of movement
- Motor learning
Explain the autonomic nervous system=
- The hypothalamus of the brain is the coordinator of the autonomic nervous system
- It consists of sympathetic & parasympathetic systems
- It controls all automated responses in the body e.g., heart rate
Explain the parasympathetic nervous system=
Known as ‘rest & digest’.
Control of your heart rate, blood pressure, digestion, urination and sweating, among other functions. Helps to control your body’s response during times of rest.
It uses a two-neuron pathway to reach target organs:
- 1st order neutron originates in the brainstem or the sacral spinal cord and sends its axon to a ganglion near or within the target organ, it releases ACH at the ganglia.
- 2nd order neutron is located in the ganglion and sends its axon to the target tissue.
Explain the sympathetic nervous system=
Known as ‘fight or flight’
Network of nerves responsible for many functions that you don’t have to think about to control. This can include control of your heart rate, blood pressure, digestion, urination and sweating, among other functions.
Signals in the spine activate paravertebral ganglia.
Neurotransmitters then release a hormone called neurepinephrine, the release of norepinephrine into the bloodstream and onto target cells activates several physiological changes associated with the fight-or-flight response.
Where can norepinephrine be produced?
Adrenal glands can produce it in the adrenal medulla.
What nuclei in the brain stem control cardiac output?
- Solitary nucleus
- Depressor area
- Pressor area
- Nucleus ambiguous
What nuclei in the brain stem control respiratory function?
- Pantine nuclei
- Ventral respiratory group
- Dorsal respiratory group
What is the role of the nervous system?
- Monitor the internal and external environment
- Process this information
- Direct behaviour and body processes
Has: sensory neuron, interneurons and motor neurons
Neuron=
Neurons are the cells that make up the brain and the nervous system. They are the fundamental units that send and receive signals. They send messages throughout the body to allow you to do everything e.g., breathing, eating etc.
Structure of a neuron:
- Cell body (soma)
- Dendrites
- Axon
- Axon hillock
- Terminal branches
What are the role of neurons/ how are they physiologically demanding?
- They control local concentrations of neurotransmitters
- Supply nutrients
- Support/ guide neuronal development
- Stabilise neuronal networks
- ‘Improve’ communication needs
- Provide immunological defence
What are the conceptual divisions of the nervous system?
Anatomical and functional
CSF and the ventricles of the brain=
- Arachnoid granulations
- Lateral ventricles
- 3rd ventricle
- Choroid plexus of the lateral ventricle
- 4th ventricle
- Choroid plexus of the 4th ventricle
- Central canal of spinal cord
Sensory cortex=
- Input from skin
- Input from proprioceptors
- Spatial discrimination
Visual cortex=
- Mapping visual input
- Visual recognition
Auditory cortex=
- Pitch, loudness, location
- Auditory memory / sound recognition
What are the functional areas of the brain?
- Motor cortex somatic
- Broca’s area
- Auditory cortex
- Sensory cortex
- Visual cortex
- Wernicke’s area
What are the main lobes of the brain?
- Frontal lobe
- Temporal lobe
- Parietal lobe
- Occipital lobe
- Cerebellum
- Brain stem
What is the language loop model?
The language loop model refers to the neural framework describing how the brain processes and produces language, involving a network of brain regions. Yep components of the language loop model:
1. Broca’s area
2. Wernicke’s area
3. Visual cortex
Somatotopy=
Refers to the precise mapping of body parts to specific areas of the brain, where stimulation of cortical points corresponds to the activation of individual muscles.
Homunculus=
The somatosensory homunculus is a brain map of your body. It’s in the sensory strip of the cortex, where sensory input like heat or pain is received. Each body part sends information to a specific part of this strip.
Prevertebral Vs Paravertebral ganglia
Prevertebral ganglia and paravertebral ganglia are components of the autonomic nervous system, differing in location and function.
Paravertebral ganglia = Near the spine, part of the sympathetic chain. Responsible for innervating structures in the body wall, thoracic organs, and some parts of the head and neck.
Prevertebral ganglia = Near major abdominal vessels, innervating internal organs. Responsible for innervating abdominal and pelvic organs
What do the adrenal glans consist of?
Medulla & cortex.
Adrenal medulla secretes epinephrine (80%) and norepinephrine (20%)
Parasympathetic vs sympathetic nervous system=
Parasympathetic= ‘Rest and digest’
Sympathetic= ‘Fight or flight response’
What are the 4 nuclei of the brain stem that control cardiac output?
- Pressor area
- Solitary nucleus
- Nucleus ambiguous
- Depressor area
What are the 3 nuclei of brain stem that control respiratory function?
- Pontine nuclei
- Ventral respiratory group
- Dorsal respiratory group
What are the functions of vagus nerves in autonomic control?
Are the main nerves of your parasympathetic nervous system. These functions are involuntary, meaning you can’t consciously control them.
The input of sensory information comes from:
- Lungs
- Bladder
- Circulatory system
- Digestive factors
What are the main gyri and sulci of the brain?
- Pre-central gyrus
- Lateral sulcus
- Post-central gyrus
- Central sulcus
What arteries supply blood to the veins?
Two pairs of arteries:
1. Internal carotid
2. Vertebral (branch of subclavian, transverse foramina)
What is the circle of willis?
A ring-like arterial structure at the base of the brain that provides critical blood supply to the brain and surrounding structures. It ensures blood flow to the brain even if the main arteries are compromises and helps balance blood pressure across the brains blood supply.
The Circle of Willis links the internal carotid arteries (from the anterior circulation) with the vertebrobasilar arteries (from the posterior circulation). Its main components include:
1. Anterior cerebral arteries
2. Anterior communicating artery
3. Internal carotid arteries
4. Posterior cerebral arteries
5. Posterior communicating arteries
The circle of willis provides an anastomosis= allow for alternative pathways for the flow of blood, lymph or other body substances ensuring continuity even if pathway is blocked.
