Brain Flashcards
List the major regions of the CNS
regions of the CNS are as follows:
Spinal cord Brainstem Cerebellum Diencephalon Cerebrum
note: retina is also
Describe spinal cord and its function
**The spinal cord is a continuation of the brainstem. It is *crucial for relaying sensory and motor information from the cerebral cortex and cerebellum to the organs and limbs.
Define and describe function and structure of brainstem
brainstem is located at the base of the skull and is continuous with the spinal cord. It is comprised of the midbrain, pons, and medulla oblongata. These areas are involved in sensory-motor relays and regulating vital autonomic functions.
The brainstem is continuous with the spinal cord. It acts as a relay station between the spinal cord and the brain’s cerebral hemispheres. The brainstem is the entry point and exit point for 10 of the 12 cranial nerves.
The brainstem is made up of the following three main parts:
Midbrain Pons Medulla oblongata
sensory motor relays;autonomic function
Define and describe funciton of cerebellum
Cerebellum
The cerebellum is located at the base of the brain, below the cerebral cortex and behind the brainstem. It is important for the timing and planning of movement, motor memory, and posture.
Define and describe diencephalon
encephalon
The diencephalon receives sensory inputs from the body, and distributes the information to the appropriate areas of the brain. It is important in the regulation of the autonomic and endocrine systems.
Define and describe cerebrum
he cerebral cortex form the outer surface of the brain, and are characterized by numerous grooves. The hemispheres can be superficially divided into several lobes. These lobes are further divided into functional areas responsible for higher reasoning, abstract thought, audio and visual processing, and memory.
Define and describe medulla
Medulla
The medulla oblongata is the most inferior portion of the brainstem and is continuous with the spinal cord. White matter structures in the medulla (called the pyramids) contain motor fibers of the corticospinal and corticobulbar tracts. These tracts carry descending motor signals from the brain to the medulla and spinal cord. At the medulla-spinal cord junction most of these pyramidal fibers decussate to the opposite side of the spinal cord [+].
The medulla contains nuclei which are involved in the regulation of cardiovascular function, respiratory rhythm and digestion, and the regulation of reflexes such as vomiting, coughing, sneezing, swallowing, and hiccuping.
cough sneeze cardiac function
Define and describe pons
The pons is the middle region of the brainstem, which contains a ventral bulge. It is located inferior to the midbrain, superior to the medulla oblongata, and anterior to the cerebellum. This region of the brainstem is composed mostly of white matter tracts and nuclei, which relay signals from the forebrain to the cerebellum.
The pons also contains nuclei involved in the control of sleep, respiration, swallowing and taste, bladder control, equilibrium, eye movement, facial expression and sensation, and posture.
pons: sleep and facial expression(CNVII)
Define and describe midbrain
Midbrain
The midbrain is the most superior portion of the brainstem, it is located just inferior to the thalamus. The midbrain contains fibers linking different components of the motor systems: the cerebral hemispheres, cerebellum, and basal ganglia. All sensory nerve tracts pass through the midbrain on their way to the thalamus [+].
The midbrain contains nuclei involved in voluntary movement, motor functions, coordination of visual and auditory reflexes, the regulation of circadian rhythms, and thermoregulation.
vol movement; visual and auditory reflexes (i,e, CNIII and CNIV for eye)
Define and describe cerebellum and function
The cerebellum is important for smooth, coordinated, and precise movements. It receives a huge amount of sensory input and fine-tunes motor activity accordingly.
The cerebellum sits dorsal to the pons and midbrain. It comprises just 10% of the brain’s total volume, but contains more than 50% of all the neurons in the brain.
Several distinct regions receive inputs from different areas of the brain and spinal cord, and have outputs to different motor systems.
Cerebellum function
The cerebellum controls the rate, range, and direction of movement. To do this, it processes information received from other brain areas:
Vestibular information Visual information Somatosensory information Motor information
The cerebellum is involved in posture and balance, and plays an important role in learning and executing motor skills. For example, riding a bike, hitting a ball, or playing the piano.
Which of the following are true and which are false of the function of the cerebellum?
- it is invovled in controlling rate, range and direction of movements
- contributes to balance and eye movements
- involved in processing sensoty info from skin
- initiates motor activity
top two are true
bottom two: job of 1- somatosensiry area of partiel lob in cerebral cortex; and primary motor cortex of frontal lobe of cer cortex
Without the use of medical equipment, what is a simple way you can assess a person’s cerebellar function?
In a neurological examination, cerebellar function is assessed by examining gait, balance (with eyes open and then shut), and finger to nose testing. People with cerebellar lesions will have difficulty with balance, even with their eyes open. They also have difficulty when asked to perform accurate rapid alternating movements. For example, repeatedly touching his or her own nose and then the examiner’s finger, or demonstrating how to screw a lightbulb into a socket.
What does damage to cerebellum do?
The cerebellum helps maintain balance and posture. Damage to the cerebellum does not prevent a person moving, but it does make actions hesitant and clumsy,i.e.difficulty performing rapod, alternating movements. and affects balance and gait
Diencephalon - structure and function
What is the structure and function of the diencephalon?
The diencephalon receives sensory inputs from every part of the body (except for olfactory inputs), and distributes this information to the appropriate regions of the brain. It is also important in regulating the endocrine and autonomic systems. In mammals, the diencephalon is covered by the cerebrum and is only visible in brain scans or when the brain is dissected.
The diencephalon sits at the top of the brainstem and comprises the following parts:
Thalamus Subthalamus Hypothalamus Epithalamus
Describe thalamus
The thalamus is the more superior portion of the diencephalon. It is the relay station for sensory information ascending to the cerebral cortex. It is composed of numerous thalamic nuclei, each of which has a functional specialty. Each thalamic nucleus sends information to, and receives input from, specific regions of the cortex.
Incoming information to the thalamus is sorted and processed before being relayed to the appropriate cerebral cortices. Overall, the thalamus is responsible for mediating sensation, motor activities, cortical arousal, learning, and memory.
note: thalamus is close to lateral and medial striae of olfactory tract
Describe hypothalamus
Hypothalamus
The hypothalamus extends inferiorly and anteriorly from the thalamus. Just inferior to the hypothalamus is the optic chiasm (where the optic nerves cross) and the pituitary gland (an endocrine organ) [+].
The hypothalamus is both a nervous and endocrine organ, with numerous functions that mostly facilitate the maintenance of homeostasis. There are seven main hypothalamic functions:
Autonomic control center Center for emotional response Regulation of body temperature Regulation of food intake Regulation of water balance and thirst Regulation of sleep-wake cycles Control of endocrine system functioning
Define and describe subthalamus and epithalamus
Subthalamus
The subthalamus is located inferior to the thalamus and lateral to the hypothalamus. The main structure in the subthalamus is the subthalamic nucleus. The subthalamic nucleus is a structure in the basal ganglia that modifies movement. However, much is still unknown about subthalamic nuclei functions.
Epithalamus
The epithalamus acts as a relay station between the senses and the cerebral cortex. The pineal gland is part of the epithalamus.
List functions of thalamus
- motor activities
- relaying sensory information
- learning
- memory
List functions of hypothalamus
- sleep wake cycles
- emotional response
- autonomic system regulation
- body temperature regulation
- food and water regulation
- endocrine system regulation
Describe function of four lobes of cerebral hemisoheres
What are the functions of the four lobes of the cerebral hemispheres?
The cerebrum is divided into left and right hemispheres. These hemispheres are entirely separate, but are connected by a white matter tract called the corpus callosum. The corpus callosum is a large bundle of neuronal axons (commissural fibres) that pass between the left and right hemispheres, and allow communication between the two hemispheres [+].
Cerebral cortex
The cerebral cortex comprises the outer layer (gray matter) of the brain and is involved in higher brain functions such as reasoning, abstract thought, and language.
Describe the sensory homunculus
The sensory homunculus is a representation of the localization of the different regions of the body in the somatosensory cortex. Note the relatively greater representation of the face and hands.
Identify the indicated items and describe their function.
Identify the indicated items and describe their function.
Identify the parts of the brainstem
Name the labelled structures
Label the numbered regions on this posterior view of the brainstem.
Label the numbered tracts
Identify the following tracts and features of an axial section of the spinal column
