Brain Flashcards

1
Q

List the major regions of the CNS

A

regions of the CNS are as follows:

Spinal cord
Brainstem
Cerebellum
Diencephalon
Cerebrum

note: retina is also

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2
Q

Describe spinal cord and its function

A

**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.

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3
Q

Define and describe function and structure of brainstem

A

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

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4
Q

Define and describe funciton of cerebellum

A

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.

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5
Q

Define and describe diencephalon

A

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.

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6
Q

Define and describe cerebrum

A

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.

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7
Q

Define and describe medulla

A

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

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8
Q

Define and describe pons

A

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)

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9
Q

Define and describe midbrain

A

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)

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10
Q

Define and describe cerebellum and function

A

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.

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11
Q

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

A

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

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12
Q

Without the use of medical equipment, what is a simple way you can assess a person’s cerebellar function?

A

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.

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13
Q

What does damage to cerebellum do?

A

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

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14
Q

Diencephalon - structure and function

A

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
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15
Q

Describe thalamus

A

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

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16
Q

Describe hypothalamus

A

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
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17
Q

Define and describe subthalamus and epithalamus

A

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.

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18
Q

List functions of thalamus

A
  • motor activities
  • relaying sensory information
  • learning
  • memory
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19
Q

List functions of hypothalamus

A
  • sleep wake cycles
  • emotional response
  • autonomic system regulation
  • body temperature regulation
  • food and water regulation
  • endocrine system regulation
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20
Q

Describe function of four lobes of cerebral hemisoheres

A

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.

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21
Q

Describe agenesis of corpus callosum and symptoms

A

Agenesis of the corpus callosum is a disorder where a baby is born with part or all of their corpus callosum missing.
Symptoms include delays in holding the head up, sitting, standing, walking, and poor hand-eye coordination. Other symptoms can include seizures, feeding problems, impaired mental and physical development, and poor visual and auditory memory.

22
Q

Describe divisions of each hemisphere

A

Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe

23
Q

Describe frontal love

A

rontal lobe

The primary motor cortex is located at the posterior border of the frontal lobes. It generates the nerve impulses that initiate movements. The premotor cortex is thought to be involved in planning these movements.

Areas in the prefrontal cortex are involved in “executive functioning”. This includes abstract thought, planning, consequences of actions, and learned social behaviors. It is thought the prefrontal cortex plays a significant role in working memory.

Broca’s area is involved in language expression [+].

24
Q

Damage in Broca’’s area can lead to

A

Broca’s area is involved in language expression. Therefore, patients with damage to this area experience difficulty speaking in complete sentences. However, language comprehension is unimpaired (that is, they can still fully understand language). This condition is called expressive (or nonfluent) aphasia. Note that language as a whole is not restricted to easily identifiable areas of the brain

25
Q

Describe the parietal lobe

A

Parietal lobe

The parietal lobe is where the somatosensory cortex is located. It integrates a variety of sensory information including auditory, visual, somatosensory, and proprioceptive information.

In the primary somatosensory cortex, there is a mapped representation of the sensory neurons in the body corresponding to body parts, which is called the sensory homunculus.

26
Q

Describe the sensory homunculus

A

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.

27
Q

Describe occipital lobe

A

The occipital lobe is where the visual cortex is located. It is divided into several visual areas. The primary visual cortex contains a well defined map of visual information received from the outside world.
Damage to occipital lobe can result in:
- varying degress and types of visual impairment
- EVEN IF EYES are undamaged
- e.g.s inability to differentiate colours, visual hallucinatins, even blindmess

28
Q

Describe temporal lobe

A

site of priamryand association auditory cortex

contains wernicke’s area: for understanding language

29
Q

Wernicke’s area damage can result in

A

Wernicke’s area is involved in language comprehension. Therefore, patients with damage to this area are unable to understand language, both spoken and written. However, these patients can still speak with normal fluency (that is, they speak with normal rhythm and syntax), but their sentences may be meaningless. This condition is called receptive (or fluent) aphasia. Note that language as a whole is not restricted to easily identifiable areas of the brain.

30
Q

Describe limbic system

A

Limbic system

The limbic lobe is an evolutionarily old cortical area. Hippocampus and the parahippocampal gyri form the floor of the inferior limb of the lateral ventricle. The limbic cortices receive information from the amygdala and olfactory cortical areas. Memory formation is linked to the hippocampus. Information from the hippocampus travels through the fornix to terminate in the mammillary bodies, nuclei of the hypothalamus. From here, the information is sent to the the anterior nuclei of thalamus, and to the frontal lobe, through the cingulate cortex.

Due to its central position and inputs from a cortical centres, the limbic system links the conscious, intellectual cortical functions with the unconscious, autonomic functions of the brain stem and diencephalon. It also facilitates memory storage and retrieval, establish emotional states, and expressing emotional states through gesturing.

31
Q

Briefly describe meninges

A
32
Q

Describe dura mater

A
33
Q

Describe arachnoid mater

A
34
Q

Describe pia mater

A
35
Q

Describe the ventricular system of brain

A

The ventricular system consists of the two lateral ventricles (left and right side of the brain), the single, midline third ventricle that lies between the left and right diencephalon (thalamus and hypothalamus). The cerebral aqueduct, that lies within the midbrain, connects the third and the fourth ventricles. The floor of the fourth ventricle is formed by the pons and part of the medulla (the ‘open’ medulla), and its roof is provided by the cerebellum.

36
Q

Define and list functions of CSF

A

Cerebrospinal fluid

Cerebrospinal fluid (CSF) is a colorless fluid that is present in and around the brain and spinal cord. The CSF performs a number of functions:

Protection: CSF forms a cushion around the brain, protecting it from physical injury.
Transport: In addition to the bloodstream, CSF helps supply nutrients to the brain and remove wastes.
Support: The brain floats in the CSF, which effectively reduces its net weight [+].
37
Q

Describe CSF circulation

A

CSF circulation

CSF created by the choroid plexuses in the ventricular system and circulates from the lateral to the IVth ventricle. CSF exits the ventricular system by moving from the IVth ventricle into the subarachnoid space, and circulate around the brain and spinal cord. It is absorbed into the bloodstream through arachnoid granulations, which project into the dural venous sinuses to allow the flow of CSF from the subarchnoid space to the dural sinuses. The arachnoid granulations are one-way valves, which means CSF can move out of the subarachnoid space, but blood cannot move into it.

38
Q

Describe choroid plexus

A

The choroid plexus is a network of cells located within the ventricular system which produce CSF. In addition, the choroid plexus has the vital function of filtering wastes, unnecessary neurotransmitters, and foreign substances out of the CSF. At any one time, adults contain ~150 mL of CSF, which is replaced every ~8 hour

39
Q

Describe the results of injury to the diencephalon

A

Could include inability to regulate body temperature, hormonal imbalances, loss of perception, amnesia

40
Q

Describe the reults of injury to the brainstem

A

Loss of consciousness, irregular heart rate and breathing

41
Q

Describe the results of injury to the cerebellum

A

Movements are hesitant and clumsy.

42
Q

Describe results of injury to corpus callosum

A

Poor coordination between opposite sides of the body

43
Q

Describe results of injury to occipital lobe

A

Varying degrees and types of visual impairment, even if the eyes remain undamaged.

44
Q

Identify the indicated items and describe their function.

A
45
Q

Identify the indicated items and describe their function.

A
46
Q

Describe the Tectum

A

In the Midbrain
The tectum is responsible for auditory and visual reflexes.
- co-ordinates visual and auditory reflexes (eg., orienting gaze to a sound or movement)
- superior colliculus receives a predominant input from the retina, that is ‘mapped’ to the visual field. Doesn’t project to cortex (therefore not to thalamus).
- inferior colliculus has predominant input from auditory field. Projects to thalamus.
- both colliculi provide ouput to other brainstem pathways, particularly the medial longitudinal fasciculus, which co-ordinates head and eye movements

47
Q

Identify the parts of the brainstem

A
48
Q

Name the labelled structures

A
49
Q

Label the numbered regions on this posterior view of the brainstem.

A
50
Q

Label the numbered tracts

A
51
Q

Identify the following tracts and features of an axial section of the spinal column

A
52
Q

What is the differnce between pre- and post-central gyrus

A

Precentral gyrus controls voluntary motor movements while postcentral gyrus controls involuntary functions.