Anatomy & Physiology Nervous System Part 2 (Test 1) Structures of the Brain

Gyrus

mountain

Sulcus and Fissure

deeper grooves and valleys between the gyri

Sulcus (sulci)

more shallow grooves

Fissure

deeper grooves between

What makes up the left and right brain

the cerebrums or the 2 cerebral hemispheres which are responsible for higher level functions

What does the left hemisphere control for most people?

- dominant for language

- understanding and using language, but also written language (reading and writing)

- responsible for reasoning

What does the right hemisphere control for most people

- extralinguistic features of language

- prosody

---- intonation - questions?

---- stress- syllables and words in a sentence

- body language

- facial expressions

How many lobes is the cerebrum divided into?

4 lobes

What fissure separates the right and left hemispheres?

Cerebral Longitudinal Fissure

What structure holds the two hemispheres together?

Corpus Colosseum

What is the cerebral cortex?

the outer surface of the cerebrum

What is the cerebral cortex made of?

made of grey matter

How many layers is the cerebral cortex made up of?

made of 6 layers that can only be seen under a microscope

What is the first layer of the cerebral cortex comprised of?

Made of Glial Cells (non-nervous cells)

- schwan, astrocytes microglial cells

What do glial cells do?

help support and protect the neurons

In what ways do glial cells help support and protect the neurons?

- provide insulation and support

- help form myelin

- help contribute to the pruning process during development

What are layers 2, 3, 5, & 6 of the cerebral cortex part of?

these layers are part of the somatic nervous system

What type of cells are within the 2, 3, 5, & 6 layers of the cerebral cortex?

they are pyramidal cells (shaped like a pyramid)

What are the pyramidal cells involved in?

- they are involved in motor function

-they help connect the cortex to other parts like the brain stem, spinal cord, basal ganglia, thalamus, cerebellum

- contribute to the initiation of motor commands

What is the 4th layer of the cerebral cortex comprised of?

- made up of non-pyramidal cells

- star shaped cells

What is the role of the 4th layer of the cerebral cortex?

- involved in sensory function

- job is to receive information from the indirect system and get it back to the parietal lobe (sensory)

What is the overall function of the cerebral cortex?

initiates motor commands but also responsible for receiving sensory information

What are the 4 lobes of the brain?

frontal, parietal, temporal, occipital

What are the characteristics of the frontal lobe?

- most anterior and largest lobe

What separates the frontal and parietal lobes?

central sulcus (of Rolando)

What are the areas neighboring the central sulcus named?

Pre-central (frontal) and post-central (parietal)

What is the pre-central sulcus also called?

the motor strip

What does the frontal lobe control?

- cognitive functioning: attention/focus, working memory, abstract thinking, problem solving, reasoning, creative thought

- executive functioning: goal directed behavior

- emotions and judgement

What does the motor strip control?

majority of voluntary coordinated motor and muscle movements are initiated and sent to the body

Where is the Broca's area located?

little anterior to the motor strip

What does the Broca's area control?

speech planning and programming

What does damage at the Broca's area cause?

- apraxia

- Broca's aphasia

What are the supplementary motor area and premotor cortex areas linked to?

- both linked to the indirect system

- both involved in the initiation and planning of motor movements

What are the characteristics of the parietal lobe?

posterior to the frontal lobe

What is the function of the parietal lobe?

primary function: sensory

Which system is the parietal lobe connected to?

the somatic system

What does the parietal lobe also contain?

the post central gyrus: sensory

What sensory functions does the parietal lobe control?

touch, temp, vibration, proprioception

What are the characteristics of the occipital lobe?

the occipital lobe is located at the back portion of the head

What is the occipital lobe also known as?

Primary visual cortex

What does the Occipital Lobe do?

- receives stimulation from the eyes

- visual stimulation processing

--- higher level: connect written words with another word or images

What separates the parietal lobe from the occipital lobe?

the parietooccipital fissure

How is it best to see the parietooccipital fissure?

easier to see from within the brain

What are the characteristics of the temporal lobe?

located on each side of the cerebrum

What is the temporal lobe's job?

- sense of hearing

- receives and processes auditory information

What are the important areas within the temporal lobes?

- Hershall's Gyrus

- Wernicke's Area

- Lateral/Sylvian Fissure

What does the Hershall's Gyrus do?

first contact for processing auditory information from the auditory pathway

What does the Wernicke's Area do?

- involved in higher level of processing auditory information

- Understand and decode language

What does damage to the Wernicke's area cause?

Wernicke's aphasia

What divides the temporal lobe from the parietal and frontal lobes?

the Lateral/Sylvian Fissure

What are hemisphere communication fibers within the temporal lobe?

- fibers that allow connection and communication

- arcuate fasciculus: part of larger bundle of fibers (superior longitudinal fasciculus)

What are the characteristics of the cerebellum?

- located inferior to most of the brain

- posterior to the brain stem

- has billions of cells

- has wrinkles and reflect the gyri of the brain: surface like the cortex

- grey matter on outside and white matter within

How many hemispheres does the cerebellum have?

two

What are the hemispheres separated by?

a vermis

In each hemisphere there are _____ peduncles which are ____________, _____________, & _______________

three

- superior

- middle

- inferior

What system does the cerebellum play a role in?

extrapyramidal system (indirect)

What type of tracts run through the cerebellum?

- both sensory and motor tracts

What are motor tracts called?

efferent

What are sensory tracts called?

afferent

What does the cerebellum help control?

has to do with posture, gate, coordination, timing of movements, precision, accuracy

---- does not initiate but participates

-- helps in the fine motor control of walking, running, balance

What is the limbic system?

- includes the cingulate gyrus

- below most of the lobes

- emotions, memory, awareness, ability to learn, and motivation

What are the characteristics of the corpus callosum?

- white tissue in picture

- connects the two hemispheres together

- where the two hemispheres communicate

What helps with communication within the corpus callosum?

- communicate via commissural axons

- inter-hemispheric communication

What are the characteristics of the Diencephalon?

- inferior or below the corpus collosum

- grey matter on either side of the 3rd ventricle

-includes the thalamus

What are the characteristics of the Thalamus?

- extrapyramidal system receiving sensory information

- associated with the basal ganglia

What are the characteristics of the Basal Ganglia?

- also part of the extrapyramidal system

- receiving sensory information

- has connections with the cortex, brainstem, thalamus

What does the Basal Ganglia do?

- Contributes to coordination of our motor movements

o Managing force, timing, accuracy

- Internal Capsule

o Fibers from the neurons

- Nuclei associated

o Substancia nigra: produces neurotransmitter Dopamine

- Parkinson's associated with dopamine difficulties

What are the protectors of the central nervous system?

meninges

What are meninges?

three protective layers (protect, hold structure in place and provide nutrients)

- made of connective tissue: type of support cell

What are the layers of the meninges?

pia matter, arachnoid matter, dura matter

What is pia mater?

- innermost lining to the brain

- very thin, contours to the brain

- has veins and arteries running through it

What is arachnoid mater?

- separates the pia from the dura mater

- between pia and arachnoid is sub arachnoid space where cerebral spinal fluid flows

What is dura mater?

- most superficial and outermost layer

- toughest

What system is cerebrospinal fluid part of?

the ventricular system

What is the purpose of the cerebrospinal fluid?

- Flows through the subarachnoid space to surround the brain and the spinal cord

- Lightens the weight of the brain through bouency

- Serves as a cushion or a buffer for neural tissue of the brain

- Transports nutrients and hormones to the brain

- Removes waste from our brain

Where is cerebrospinal fluid produced?

- Associated with ventricle and canals and the choroid plexus

- It is produced within the ventricles via the choroid plexus

- CSF is produced mostly in the laterals, but is produced in all the ventricles

- Intraventricular foramen: laterals connected to the third through this

- 3rd-4th cerebral aqueduct

- Central canal on the spinal cord

- These allow for movement of CSF through the brain and spinal cord

- Replenished every 7 hours, through absorption and the venous system (veins)

What is the supplier of the brain?

the circle of willis

What is the circle of willis?

keeps the pressure of the blood equal flowing in the brain?

What two arteries deliver oxygenated blood to the brain?

1. Internal Carotids

2. Vertebral Arteries

The internal carotid arteries are branches of what?

the common carotid arteries

The internal carotid arteries bifurcate into what?

internal and external carotid arteries

The vertebral arteries come together to form what?

Basilar Artery

The basilar artery courses upwards and branches to what?

Posterior Cerebral Artery

What branches from the posterior cerebral artery from each side?

posterior communicating arteries

The posterior communicating arteries connect to what?

internal carotid artery

What does the vertebral artery supply?

brainstem, cerebellum, and part of the occipital and temporal lobes

What does the posterior cerebral artery (from basilar) supply?

part of occipital and inferior part of temporal

What does the middle cerebral artery supply?

lateral surface of cerebral hemispheres and branches to basal ganglia and internal capsule and language areas in this lateral region

What does the anterior cerebral artery supply?

- medial frontal and parietal lobes

- and the corpus callosum

What is the blood brain barrier?

- protects any substance or bacteria from entering the brain

- regulates what gets in and what does not

Why is gestation important for fetuses?

the blood brain barrier is not fully developed

What are the characteristics of the brainstem?

located inferior rot he hemispheres and is just in front of the cerebellum

What can be a name used to describe the brainstem?

bulbar

The brainstem serves as the intermediate stage of organization between what?

simple reflexive movements/responses from the spinal cord to our complex fine tuned responses that come from the cerebral cortex

What type of tracts does the brainstem contain?

both motor and sensory tracts

What cranial nerves are on the brainstem?

III-XII

What is the brainstem responsible for?

life functions: consciousness, breathing, heart rate, blood pressure, sleep wake cycle

What is the reticular formation

a nerve network in the brainstem that plays an important role in controlling arousal (alertness/awakeness)

What does the brainstem communicate with?

cerebellum and cerebral cortex

What are the parts of the brainstem?

midbrain, pons, medulla oblongata