Structure and function of the nervous system Flashcards
What the nervous system divided into?
- The central nervous system
2. Peripheral nervous system - somatic and autonomic
What are the fundamental and complex processes the brain controls?
Basic’ fundamental life processes:
• Breathing
• Organ function
• Movement
Complex’ processes:
• Thought
• Behaviour and emotion
• Creating memories
What are the major brain regions?
Forebrain • Telencephalon (or cerebrum) • Diencephalon Brainstem • Midbrain • Pons • Medulla oblongata Cerebellum
Describe the axes of the brain
Anterior-posterior • Anterior = Front • Posterior = Behind Rostral-caudal • Rostral = “Nose” • Caudal = “Tail” Dorsal-ventral • Dorsal = Top • Ventral = Bottom Superior-inferior • Superior = Above • Inferior = Below
What are the 3 planes of the brain?
Coronal
• Divide the brain into a front (anterior) and a back (posterior) section
Horizontal
• Divide the brain into an upper (superior) and lower (inferior) section
Sagittal
• Divide the brain into two hemispheres
• Further characterized as midsagittal (midline) or parasagittal (more lateral)
Where is the hippocampus located?
What is the function of the hippocampus?
The hippocampus (derived from the Greek for “seahorse”) is a region of the cerebral cortex embedded deep within the temporal lobe.
- Learning
- Memory formation and retrieval
- Regulation of hypothalamus-pituitary-adrenal (HPA) axis
Why are coronal, horizontal and sagital sections important?
Coronal sections can reveal important regions within the forebrain, including various sub-cortical structures (e.g. the hippocampus):
Horizontal sections
Horizontal sections can reveal important regions within the forebrain, including various sub-cortical structures (e.g. the hippocampus):
Sagittal sections
Sagittal sections can reveal important regions within the forebrain, including various sub-cortical structures (e.g. the hippocampus):
What are the cranial nerves?
The cranial nerves describe the twelve (I-XII) pairs of nerves arising from the brainstem that perform a diverse range of functions.
What is the function of the first 2 cranial nerves?
Cranial nerve I (Olfactory)
• Special sensory – sensation of smell
Cranial nerve II (Optic)
• Special sensory – sensation of vision
What does cranial nerve 3 do (III)?
Cranial nerve III (Oculomotor)
• Somatic motor – eye and eyelid movement
• Visceral (autonomic) motor – parasympathetic control of pupil size
What does cranial nerve 4 do (IV)?
Cranial nerve IV (Trochlear)
• Somatic motor – eye movement
What does cranial nerve 5 do (V)?
- Somatic sensory – sensation of touch to the face
* Somatic motor – movement of muscles of mastication (chewing)
What does cranial nerve 6 (VI) do?
• Somatic motor – eye movement
What does cranial nerve 7 (VII) do?
- Somatic sensory – movement of muscles of facial expressions
- Special sensory – sensation of taste in anterior tongue
What does cranial nerves 8 (VIII) do?
- Auditory-vestibular (vestibulocochlear) nerve
* Special sensory – hearing and balance
What does cranial nerve 9 (IX) do?
- Special sensory – sensation of taste in posterior tongue
- Visceral sensory – detection of blood pressure changes in the aorta
- Somatic motor – movement of muscles in the throat
- Visceral motor – parasympathetic control of salivary glands
What does cranial nerve 10 (X) do?
- Visceral sensory – sensation of pain associated with viscera (internal organs)
- Somatic motor – movement of muscles in the throat
- Visceral motor – parasympathetic control of heart, lungs and abdominal organs
What does cranial nerve 11 (XI) do?
• Somatic motor – movement of muscles in the throat and neck
What does cranial nerve 12 (XII) do?
• Somatic motor – movement of the tongue (e.g. swallowing and speech)
What is the meninges and its function?
The meninges describe the three membranous layers that cover the brain (and spinal cord).
From superficial to deep, the meninges comprise:
• Dura mater
• Arachnoid mater
• Pia mater
Meninges function?
• Primary function is in the protection of the brain and spinal cord
• Passage of cerebrospinal fluid (CSF) – ventricular system
• Support of cerebral and spinal blood vessels – vasculature system
What is the ventricular system of the brain?
What produces the cerebrospinal fluid?
What is the function of the ventricular system?
the ventricular system comprises a series of interconnected, cerebrospinal fluid (CSF)-filled spaces that lie at the core of forebrain and brain stem.
The ventricular system comprises:
• Lateral ventricles
• Third ventricle
• Fourth ventricle
The choroid plexus is responsible for producing the cerebrospinal fluid (CSF) that fills these ventricular spaces
Ventricular system function?
- Protection of the brain (e.g. cushion for physical shocks)
- Transport (e.g. nutrients, waste products)
- Other functions include regulation of buoyancy
Describe the vasculature of the brain?
Two pairs of arteries supply blood to the brain: the internal carotid arteries and the vertebral arteries.
- Anterior circulation is derived from the internal carotid arteries – supplies the forebrain (cerebrum and diencephalon)
- Posterior circulation is derived from the vertebral arteries – supplies the brainstem, cerebellum and upper spinal cord
Describe the positioning of both the vertebral and internal carotid arteries
- Vertebral arteries
• Vertebral arteries converge near base of pons to form the basilar artery
• Basilar artery splits into the right and left superior cerebellar arteries and the posterior cerebral arteries at the level of the midbrain
• Posterior cerebral arteries send branches – posterior communicating arteries – that connect to the internal carotid arteries - Internal carotid arteries
• Internal carotid arteries branch to form middle cerebral arteries and the anterior cerebral arteries
• Anterior cerebral arteries are connected by the anterior communicating artery
• Ring of connected arteries form the circle of Willis at the base of the brain
What is the function of the vasculature system?
- Delivery of oxygen (O2)
- Removal of carbon dioxide (CO2)
- Transport (e.g. nutrients, waste products)
