Fatima Adam
Structure of the Nervous System, the Cranial Nerves (Physiology 2)
Structure of the Nervous System (Cranial Nerves) - Dr Dean Semmens Lecture Outline Welcome to the Structure of the Nervous System (Cranial Nerves) lecture. In Fundamentals of Physiology and Pharmacology, you learned how individual neurons function and communicate. Now we are ready to assemble them into a nervous system that sees, hears, feels, moves, remembers, and dreams. Just as an understanding of neuronal structure is necessary for understanding neuronal function, we must understand nervous system structure in order to understand brain function. Desired Learning Outcomes By the end of this lecture, students should be able to: Orientate and identify brain slices and regions with respect to each other List, in order, the cranial nerves, and their basic functions Describe structures involved in protection and support in the brain Session Resources You can find the full set of PowerPoint slides for the lecture HERE Download HERE. You can find a Kahoot! quiz for the lecture HERELinks to an external site.. Session Activities Activity 1. Axes and Planes of the Brain In this video, we will discuss the axes and planes of the brain. At the end of the video, you will find a short "test your knowledge" activity. Activity 2. Cranial Nerves In this video, we will discuss each of the twelve cranial nerves and their respective functions: Activity 3. Protection and Support of the Brain In this video, we will discuss the protection and support of the brain in terms of the meninges, the ventricular system and the brains vasculature system: Activity 4. Kahoot Quiz In order to test your knowledge at the end of the lecture, you can find a Kahoot! quiz for the lecture HERELinks to an external site.. Further Reading If you would like to read further or consolidate your knowledge on the topic, I would recommend the following further reading: Neuroscience: Exploring the Brain 3rd or 4th Edition (Bear, Connors, Paradiso) Chapter 7. Any Questions? If you have any questions on the lecture, please feel free to add it to the Padlet discussion board below. Alternatively, please do me email me (dsemmens@sgul.ac.uk) and I'll be very happy to help. I have left some student questions from last year on the Padelt discussion board, just incase this may help with any similar questions that you may have: Made with Padlet Glossary Afferent – Nerves that are conducting information to a location Anterior – Nearer the front Arachnoid membrane - A fine, delicate membrane, the middle one of the three membranes or meninges that surround the brain and spinal cord, situated between the dura mater and the pia mater. Brain - An organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating centre of sensation and intellectual and nervous activity. Brain stem - The central trunk of the mammalian brain, consisting of the medulla oblongata, pons, and midbrain, and continuing downwards to form the spinal cord. Caudal – At or near the tail or the posterior part of the body Central nervous system - The complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord. Cerebellum - The part of the brain at the back of the skull in vertebrates, which coordinates and regulates muscular activity. Cerebrospinal fluid - Clear watery fluid which fills the brains ventricles and the space between the arachnoid membrane and the pia mater. Cerebrum - The principal and most anterior part of the brain in vertebrates, located in the front area of the skull and consisting of two hemispheres, left and right, separated by a fissure. Choroid plexus - A network of blood vessels in each ventricle of the brain, producing the cerebrospinal fluid Contralateral - Relating to or denoting the side of the body opposite to that on which a particular structure or condition occurs. Coronal – Relating to the crown of the head Cranial nerve - Each of twelve pairs of nerves which arise directly from the brain, not from the spinal cord, and pass through separate apertures in the skull. Dorsal - On or relating to the upper side or back of an animal, plant, or organ. Dura mater - The tough outermost membrane enveloping the brain and spinal cord. Efferent – Nerves that are conducting information from a location Ipsilateral - Belonging to or occurring on the same side of the body Lateral – Of, at, towards, or from the side Lymphatic system - The network of vessels through which lymph drains from the tissues into the blood. Medial – Situated in the middle Meninges - The three membranes (the dura mater, arachnoid, and pia mater) that line the skull and vertebral canal and enclose the brain and spinal cord. Midline - A median line or plane of bilateral symmetry, especially that of the body. Midsagittal plane - The median vertical longitudinal plane that divides a bilaterally symmetrical animal into right and left halves — called also median plane. Pia mater - The delicate innermost membrane enveloping the brain and spinal cord. Posterior – Further back in position Rostral - Situated or occurring near the front end of the body, especially in the region of the nose and mouth Sagittal - Relating to the suture on top of the skull which runs between the parietal bones in a front to back direction. Spinal cord - The cylindrical bundle of nerve fibres and associated tissue which is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system Ventral - On or relating to the underside of an animal or plant; abdominal Ventricular system - A set of four interconnected cavities (ventricles) in the brain
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What are the two main components of the human nervous system? (2)
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
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What does the central nervous system (CNS) consist of? (2)
Brain
Spinal cord
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What are the two subdivisions of the peripheral nervous system (PNS)? (2)
Somatic Nervous System
Autonomic Nervous System
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What is the role of the somatic nervous system? (2)
Controls voluntary movements of skeletal muscles.
Transmits sensory and motor signals between the CNS and the body.
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What is the function of the autonomic nervous system? (3)
Regulates involuntary processes, such as heart rate, digestion, and respiratory rate.
Operates below the level of consciousness.
Maintains homeostasis in the body.
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What are the axes and planes of the brain used for? (2)
To describe the orientation and location of brain structures.
Provide a standardized framework for studying the brain.
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What are the two main types of processes controlled by the brain? (2)
‘Basic’ fundamental life processes
‘Complex’ processes
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What are some examples of ‘basic’ fundamental life processes controlled by the brain? (3)
Breathing
Organ function
Movement
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What are some examples of ‘complex’ processes controlled by the brain? (3)
Thought
Behaviour and emotion
Creating memories
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Why is the brain considered the most complex organ in the human body? (2)
It controls ‘basic’ fundamental life processes, such as breathing and movement.
It governs ‘complex’ processes, such as thought and memory creation.
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What are the three main parts of the brain? (3)
Forebrain
Brainstem
Cerebellum
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What are the two key subdivisions of the forebrain? (2)
Telencephalon (or Cerebrum)
Diencephalon
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What are the three main components of the brainstem? (3)
Midbrain
Pons
Medulla Oblongata
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What is the role of the cerebellum? (2)
Coordinates voluntary movements like posture, balance, and speech.
Ensures smooth and precise motor activity.
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What does the anterior-posterior axis of the brain refer to? (2)
Anterior: Front of the brain.
Posterior: Behind the brain.
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What does the rostral-caudal axis of the brain refer to? (2)
Rostral: Towards the nose.
Caudal: Towards the tail
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What does the dorsal-ventral axis of the brain refer to? (2)
Dorsal: Top of the brain.
Ventral: Bottom of the brain.
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What does the superior-inferior axis of the brain refer to? (2)
Superior: Above.
Inferior: Below.
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What does the coronal plane divide the brain into? (2)
A front (anterior) section.
A back (posterior) section.
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What does the sagittal plane divide the brain into, and how is it further characterized? (3)
Divides the brain into two hemispheres.
Midsagittal: Cuts along the midline of the brain.
Parasagittal: Cuts more laterally, away from the midline.
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What does the horizontal plane divide the brain into? (2)
An upper (superior) section.
A lower (inferior) section.
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What is the hippocampus, and where is it located? (2)
The hippocampus is a region of the cerebral cortex.
It is embedded deep within the temporal lobe.
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What are the primary functions of the hippocampus? (3)
Learning.
Memory formation and retrieval.
Regulation of the hypothalamus-pituitary-adrenal (HPA) axis.
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What are two types of amnesia caused by hippocampal dysfunction, as seen in Clive Wearing's case? (2)
Anterograde amnesia: Inability to create new memories.
Retrograde amnesia: General inability to recall past memories.
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What caused Clive Wearing's hippocampal dysfunction, and what were the effects? (3)
Caused by a virus that damaged his hippocampus.
Effects included anterograde amnesia and retrograde amnesia.
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What can coronal sections of the brain reveal? (2)
Important regions within the forebrain.
Various sub-cortical structures, such as the hippocampus.
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What can horizontal sections of the brain reveal? (2)
Important regions within the forebrain.
Various sub-cortical structures, such as the hippocampus.
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What can sagittal sections of the brain reveal? (2)
Important regions within the forebrain.
Various sub-cortical structures, such as the hippocampus.
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How many cranial nerves are there, and where do they arise from? (2)
There are twelve pairs of cranial nerves (I-XII).
They arise from the brainstem.
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What is the function of cranial nerves? (1)
Cranial nerves perform a diverse range of functions.
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What is the mnemonic for remembering the cranial nerves? (12)
I. Olfactory: Oh!
II. Optic: Oh!
III. Oculomotor: Oh!
IV. Trochlear: To
V. Trigeminal: Touch
VI. Abducens: And
VII. Facial: Feel
VIII. Auditory-vestibular (Vestibulocochlear): Very
IX. Glossopharyngeal: Good
X. Vagus: Velvet
XI. Spinal accessory: Such
XII. Hypoglossal: Heaven!
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What is the function of Cranial Nerve I (Olfactory)? (1)
Special sensory: Responsible for the sensation of smell.
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What is the function of Cranial Nerve II (Optic)? (1)
Special sensory: Responsible for the sensation of vision.
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What are the functions of Cranial Nerve III (Oculomotor)? (2)
Somatic motor: Controls eye and eyelid movement.
Visceral (autonomic) motor: Provides parasympathetic control of pupil size.
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What is the function of Cranial Nerve IV (Trochlear)? (1)
Somatic motor: Controls eye movement.
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What are the functions of Cranial Nerve V (Trigeminal)? (2)
Somatic sensory: Provides sensation of touch to the face.
Somatic motor: Controls movement of muscles involved in mastication (chewing)
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What is the function of Cranial Nerve VI (Abducens)? (1)
Somatic motor: Controls eye movement, specifically innervating the lateral rectus muscle to abduct the eye.
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What are the functions of Cranial Nerve VII (Facial)? (2)
Somatic motor: Controls movement of muscles for facial expressions.
Special sensory: Provides sensation of taste in the anterior tongue.
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What is the function of Cranial Nerve VIII (Vestibulocochlear)? (1)
Special sensory: Responsible for hearing and balance.
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What are the functions of Cranial Nerve IX (Glossopharyngeal)? (4)
Special sensory: Provides sensation of taste in the posterior tongue.
Visceral sensory: Detects blood pressure changes in the aorta.
Somatic motor: Controls movement of muscles in the throat.
Visceral motor: Provides parasympathetic control of salivary glands.
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What are the functions of Cranial Nerve X (Vagus)? (3)
Visceral sensory: Detects pain associated with viscera (internal organs).
Somatic motor: Controls movement of muscles in the throat.
Visceral motor: Provides parasympathetic control of the heart, lungs, and abdominal organs.
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What is the function of Cranial Nerve XI (Spinal Accessory)? (1)
Somatic motor: Controls movement of muscles in the throat and neck.
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What is the function of Cranial Nerve XII (Hypoglossal)? (1)
Somatic motor: Controls movement of the tongue, essential for swallowing and speech.
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What are the components of the brain's protection and support? (3)
Ventricular system: A series of interconnected cavities filled with cerebrospinal fluid (CSF) that cushions and nourishes the brain.
Meninges: Three layers of protective tissue (dura mater, arachnoid mater, and pia mater) that surround and protect the brain and spinal cord.
Vasculature system: The network of blood vessels that supply oxygen and nutrients to the brain, including the cerebral arteries and veins.
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What are the three layers of the meninges? (3)
Dura mater: The outermost, tough layer that provides the brain with protection.
Arachnoid mater: The middle layer, which is web-like and cushions the brain.
Pia mater: The innermost layer, which closely adheres to the brain and spinal cord, providing a thin, protective barrier.
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What are the functions of the meninges? (3)
Protection: The meninges protect the brain and spinal cord from physical damage.
Passage of cerebrospinal fluid (CSF): The meninges support the circulation of CSF within the ventricular system.
Support of blood vessels: The meninges help support the cerebral and spinal blood vessels in the vasculature system.
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What are the components of the ventricular system? (3)
Lateral ventricles: Paired cavities within the cerebral hemispheres.
Third ventricle: A midline cavity located between the left and right thalamus.
Fourth ventricle: Located between the brainstem and cerebellum, connected to the third ventricle.
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What are the functions of the ventricular system? (3)
Protection: Cushions the brain against physical shocks by providing a buffer of cerebrospinal fluid (CSF).
Transport: Facilitates the movement of nutrients and the removal of waste products.
Regulation of buoyancy: Helps maintain the buoyancy of the brain, reducing pressure on neural structures.
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What is the role of the choroid plexus in the ventricular system? (1)
The choroid plexus is responsible for producing cerebrospinal fluid (CSF), which fills the ventricular spaces and serves various functions such as protection and nutrient transport.
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What is the source and function of the anterior circulation in the brain? (2)
Source: Derived from the internal carotid arteries.
Function: Supplies blood to the forebrain, which includes the cerebrum and diencephalon.
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What is the source and function of the posterior circulation in the brain? (2)
Source: Derived from the vertebral arteries.
Function: Supplies blood to the brainstem, cerebellum, and upper spinal cord.
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What are the two main pairs of arteries supplying blood to the brain? (2)
Internal carotid arteries
Vertebral arteries
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What happens when the vertebral arteries converge near the base of the pons? (2)
The vertebral arteries converge near the base of the pons to form the basilar artery.
The basilar artery then splits into the right and left superior cerebellar arteries and the posterior cerebral arteries at the level of the midbrain.
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What is the function of the posterior cerebral arteries in the brain's vasculature? (2)
The posterior cerebral arteries send branches called posterior communicating arteries.
These branches connect the posterior cerebral arteries to the internal carotid arteries.
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What are the two pairs of arteries that supply blood to the brain? (2)
Vertebral arteries
Internal carotid arteries
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What do the internal carotid arteries branch into, and how are they connected? (3)
The internal carotid arteries branch into the middle cerebral arteries and the anterior cerebral arteries.
The anterior cerebral arteries are connected by the anterior communicating artery.
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What forms the Circle of Willis, and where is it located? (2)
The Circle of Willis is formed by a ring of connected arteries.
It is located at the base of the brain.
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What are the primary functions of the vasculature system in the brain? (3)
Delivery of oxygen (O2) to the brain.
Removal of carbon dioxide (CO2).
Transport of nutrients and waste products.
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What is the function of afferent nerves? (1)
Afferent nerves conduct information to a location.
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What is the arachnoid membrane, and where is it located? (2)
The arachnoid membrane is a fine, delicate membrane.
It is the middle membrane of the three meninges, situated between the dura mater and pia mater.
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What is the brain, and what is its function? (2)
The brain is an organ of soft nervous tissue contained in the skull of vertebrates.
It functions as the coordinating center of sensation, intellectual activity, and nervous activity.
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What is the brainstem, and what does it consist of? (3)
The brainstem is the central trunk of the mammalian brain.
It consists of the medulla oblongata, pons, and midbrain.
It continues downwards to form the spinal cord.
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What does caudal refer to? (1)
Caudal refers to being at or near the tail or posterior part of the body.
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What does the central nervous system comprise? (2)
The central nervous system comprises the brain and spinal cord.
It controls the activities of the body.
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What is the role of the cerebellum? (1)
The cerebellum coordinates and regulates muscular activity.
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What is cerebrospinal fluid and where is it found? (2)
Cerebrospinal fluid is a clear, watery fluid.
It fills the brain's ventricles and the space between the arachnoid membrane and pia mater.
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What is the cerebrum, and where is it located? (2)
The cerebrum is the principal and most anterior part of the brain.
It is located in the front area of the skull and consists of two hemispheres.
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What is the function of the choroid plexus? (1)
The choroid plexus produces cerebrospinal fluid (CSF).
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What does contralateral refer to? (1)
Contralateral refers to the side of the body opposite to where a structure or condition occurs.
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What does coronal refer to in anatomy? (1)
Coronal refers to a plane relating to the crown of the head.
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What are cranial nerves, and where do they arise from? (2)
Cranial nerves are twelve pairs of nerves.
They arise directly from the brain, not from the spinal cord.
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What does dorsal refer to in anatomy? (1)
Dorsal refers to the upper side or back of an animal, plant, or organ
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What is the dura mater? (1)
The dura mater is the tough outermost membrane enveloping the brain and spinal cord.
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What do efferent nerves do? (1)
Efferent nerves conduct information from a location.
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What does ipsilateral refer to? (1)
Ipsilateral refers to being on the same side of the body.
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What is the lymphatic system, and what is its function? (1)
The lymphatic system is a network of vessels through which lymph drains from tissues into the blood.
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What does medial refer to? (1)
Medial refers to something situated in the middle.
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What are the meninges, and what is their function? (2)
The meninges are the three membranes (dura mater, arachnoid, pia mater) that line the skull and vertebral canal.
They enclose and protect the brain and spinal cord.
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What is the midline? (1)
The midline is a median line or plane of bilateral symmetry, especially in the body.
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What is the midsagittal plane? (1)
The midsagittal plane is the vertical longitudinal plane that divides a bilaterally symmetrical animal into right and left halves.
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What is the pia mater? (1)
The pia mater is the delicate innermost membrane enveloping the brain and spinal cord.
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What does posterior refer to? (1)
Posterior refers to something that is further back in position.
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What does rostral refer to? (1)
Rostral refers to being situated near the front end of the body, especially in the region of the nose and mouth.
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What is the sagittal plane? (1)
The sagittal plane is the plane that runs between the parietal bones in a front-to-back direction.
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What is the spinal cord, and what is its function? (2)
The spinal cord is a cylindrical bundle of nerve fibers and associated tissue.
It connects nearly all parts of the body to the brain and forms the central nervous system.
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What does ventral refer to? (1)
Ventral refers to something on or relating to the underside or abdominal part of an animal or plant.
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What is the ventricular system of the brain? (1)
The ventricular system is a set of four interconnected cavities (ventricles) in the brain.
