Biology 161 Lab – Brain and Ventricles

Brain Structures Hypothalamus – found below the thalamus it caps the brain stem and forms the walls of the 3 rd ventricle. It is the main visceral control center and vital in overall body homeostasis functions including: 1. Autonomic Control Center 2. Center for Emotional Response 3. Body Temperature Regulation 4. Regulation of food Intake 5. Regulation of water balance 6. Regulation of sleep-wake cycles 7. Control of Endocrine Function Hypothalamus

Brain Structures Pituitary Gland – sits securely in the sella turcica of the sphenoid bone. It is shaped like a pea at the end of a stalk. It is a major endocrine organ secreting at least 9 hormones including growth hormone, thyroid stimulating hormone, follicle stimulating hormone and oxytocin to name a few. It is a major endocrine organ secreting at least 9 hormones including growth hormone, thyroid stimulating hormone, follicle stimulating hormone and oxytocin to name a few. Pituitary Gland

Brain Structures Corpus Callosum – is the largest commissure which by definition connect the two hemispheres of the brain. It lies superior to the lateral ventricles. it allows the two hemispheres to coordinated function it allows the two hemispheres to coordinated function Corpus Callosum

Brain Structures Pons – “bridge” is the bulge in the brainstem between the midbrain and the medulla oblongata. Is chiefly composed of conduction fibers which complete the pathway between the higher brain centers and the spinal cord. Is chiefly composed of conduction fibers which complete the pathway between the higher brain centers and the spinal cord. Pons

Brain Structures Medulla Oblongata – the most inferior part of the brain stem. It blends into the spinal cord at the base. Plays a crucial role in the autonomic reflex center. Important visceral motor nuclei include Plays a crucial role in the autonomic reflex center. Important visceral motor nuclei include 1.Cardiovascular center 2.Respiratory centers 3.Additional centers that control Vomiting, hiccupping, swallowing, coughing and sneezing. Medulla Oblongata

Brain Structures Cerebellum – “Small Brain” accounts for about 11% of total brain mass. Located dorsal to the medulla and pons. Processes information from the cerebral motor cortex and visual and equilibrium pathways, and “instructs” motor centers which result in proper balance, posture, smooth coordinated skeletal muscle movements. Processes information from the cerebral motor cortex and visual and equilibrium pathways, and “instructs” motor centers which result in proper balance, posture, smooth coordinated skeletal muscle movements. Cerebellum

Brain Structures Thalamus – “inner room” is a deep well hidden brain region. It contains a large number of nuclei. Each nuclei receives and deciphers information from the cerebral cortex and other areas “relay station”. The thalamus plays an integral in mediating sensation, motor activities, cortical arousal, learning and memory. Each nuclei receives and deciphers information from the cerebral cortex and other areas “relay station”. The thalamus plays an integral in mediating sensation, motor activities, cortical arousal, learning and memory. Thalamus

Brain Structures Midbrain – a conduction pathway between the higher and lower brain centers. Contains the corpora quadrigemina Midbrain

Brain Structures Corpora quadrigemina – “quadruplets” which is 4 raised dome-like protrusions on the dorsal midbrain surface. 1. Visual reflex center – coordinates head and eye movements to follow moving objects. 2. Auditory Reflex center – reflexive response to sharp sounds that cause you to turn your head towards and startling sound “startle reflex” Corpora Quadrigemina

Brain Structures Cerebrum – gray matter localizes and interprets sensory inputs. 1. Controls voluntary and skilled skeletal muscle activity. 2. Functions in intellectual and emotional processing 3. Important in initiation of skeletal muscle movements Cerebrum

Cerebral Lobes Frontal Lobe Temporal Lobe Cerebellum Parietal Lobe Occipital Lobe

Brain Structures - Ventricles Are continuous spaces which reside inside the tissue of the brain Are continuous spaces which reside inside the tissue of the brain They are continuous with the central canal of the spinal cord. They are continuous with the central canal of the spinal cord. They are full of Cerebral Spinal Fluid They are full of Cerebral Spinal Fluid

Brain Structures - CSF CSF (Cerebral Spinal Fluid) – is found in and around the brain and spinal cord. It forms and liquid cushion and gives buoyancy around the CNS. The CSF reduces the weight of the brain by 97% and prevents the brain from crushing itself. It forms and liquid cushion and gives buoyancy around the CNS. The CSF reduces the weight of the brain by 97% and prevents the brain from crushing itself. It also protects the CNS from trauma and helps nourish the brain. It also protects the CNS from trauma and helps nourish the brain.

Brain Structures - CSF Choroid Plexus – these structures hang from the roof of the ventricles and produce CSF. Arachnoid Villi – knob like projections which protrude through the dura matter into the superior sagittal sinus. CSF is absorbed into the venous blood of the sinus here. Choroid Plexus Arachnoid Granulations

Brain Structures - Ventricles 1 st and 2 nd Ventricles “lateral ventricles” are deep within either cerebral hemisphere. “lateral ventricles” are deep within either cerebral hemisphere. Are large C-shaped ventricles Are large C-shaped ventricles Foramen of Munroe – “interventricular foramen” which attaches the lateral ventricles to the narrow 3 rd ventricle “interventricular foramen” which attaches the lateral ventricles to the narrow 3 rd ventricle 1 st and 2 nd Ventricles

Brain Structures - Ventricles 3 rd Ventricle Thin medial ventricle Thin medial ventricle Aqueduct of Sylvius “ cerebral aqueduct” “ cerebral aqueduct” connects the 3 rd and forth ventricle connects the 3 rd and forth ventricle 3 rd Ventricle Aqueduct of Sylvius

Brain Structures - Ventricles 4 th Ventricle – lies in dorsal to the pons and superior medulla. It is continuous with the central canal of the spinal cord. lies in dorsal to the pons and superior medulla. It is continuous with the central canal of the spinal cord. Central Canal of Spinal Cord - Continues down the spinal cord from the ventricles of the brain. Continues down the spinal cord from the ventricles of the brain. Central Canal 4 th Ventricle

Hydrocephalus “Water on the brain” is a condition where the CSF cannot be drained or reabsorbed. “Water on the brain” is a condition where the CSF cannot be drained or reabsorbed. CSF accumulates and exerts pressure on the brain CSF accumulates and exerts pressure on the brain

Hydrocephalus Hydrocephalus is treated by inserting a shunt into the ventricles to drain the excess fluid into a vein in the neck. Hydrocephalus is treated by inserting a shunt into the ventricles to drain the excess fluid into a vein in the neck.

Brain Structures - Meninges Meninges – “membrane” are three connective tissue membranes that lie just outside the CNS (Brain and Spinal Cord). Their functions include; 1. Cover and protect the CNS 2. Protect blood vessels and enclose the venous sinuses 3. Contain CSF 4. Form partitions in the skull

Brain Structures - Meninges

Dura Mater – “tough mother” is the strongest layer. “tough mother” is the strongest layer. Two layered sheet of fibrous connective tissue. Two layered sheet of fibrous connective tissue. Arachnoid - Forms a loose brain covering. Forms a loose brain covering. Separated from the dura matter by a serous cavity “Subdural space” Separated from the dura matter by a serous cavity “Subdural space” The “subdural space” is filled with fluid The “subdural space” is filled with fluid Dura Matter Superior Sagittal Sinus Arachnoid

Brain Structures - Meninges Subarachnoid Space Web-like extensions span this space and attach the arachnoid to the pia matter. Web-like extensions span this space and attach the arachnoid to the pia matter. This space is filled with CSF and large blood vessels This space is filled with CSF and large blood vessels Pia Mater “gentle mother” is composed of delicate connective tissue and is full of tiny blood vessels. “gentle mother” is composed of delicate connective tissue and is full of tiny blood vessels. This is the only layer that clings tightly to the brain following every contour. This is the only layer that clings tightly to the brain following every contour.

Spina Bifida “forked spine” results from the incomplete formation of the vertebral arches “forked spine” results from the incomplete formation of the vertebral arches 3 Types 1. Spina bifida occulta – not severe results in a small tuft of hair on the back and has no neurological ramifications. 2. Spina bifida meningocele – more severe, a sac- like cyst protrudes from the child’s spine. The cyst contains CSF and Meninges. 3. Spina bifida myelomeningocele – similar to above only the cyst contains neural structures. The more neurological structures the cyst contains the more neurological impairment.

Spina Bifida There is no treatment for the neurological defects caused by spina bifida. There is no treatment for the neurological defects caused by spina bifida. Doctors will perform surgery to close the vertebral column to prevent further damage and infection. Doctors will perform surgery to close the vertebral column to prevent further damage and infection. An infant with Spina Bifida