Lab 2 - Brain

Question 1

What do the brain and spinal chord develop from?

Answer 1

ectodermal neural tube

Question 2

What are the four major parts of the brain?

Answer 2

brain stem, cerebellum, diencephalon, and cerebrum

Question 3

What is the brain stem?

Answer 3

Consists of the medulla oblongata, pons, and midbrain and is continuous with the spinal chord

Question 4

Is the diencephalon superior or anterior to brain stem?

Answer 4

superior

Question 5

What does the diencephalon consist of?

Answer 5

thalamus, hypothalamus, and epithalamus

Question 6

What area of the brain is the largest?

Answer 6

cerebrum

Question 7

What are the brains protective coverings?

Answer 7

Cranium and cranial meninges

Question 8

Cranial meninges are continuous and share names with what?

Answer 8

spinal meninges

Question 9

What are the layers of cranial meninges?

Answer 9

dura mater, arachnoid mater and pia mater

Question 10

The dura mater is what layer of the cranial meninges?

Answer 10

outer

Question 11

The arachnoid mater is what layer of the cranial meninges?

Answer 11

middle

Question 12

The pia mater is what layer of the cranial meninges?

Answer 12

inner

Question 13

Difference between cranial dura mater and spinal dura mater?

Answer 13

the cranial dura mater has two layers; the spinal dura mater has only one

Question 14

What are the two dura mater layers called?

Answer 14

Periosteal (outer) and minengeal (inner) layer

Question 15

Role of the dura mater layers (dural layers)?

Answer 15

The dural layers around the brain are fused together except where they separate to enclose the dural venous sinuses (endothelial-lined venous channels) that drain venous blood from the brain and deliver it into the internal jugular veins. Also, there is no epidural space around the brain.

Question 16

What is cerebrospinal fluid?

Answer 16

is a clear, colourless liquid composed primarily of water that protects the brain and spinal cord from chemical and physical injuries. It also carries small amounts of oxygen, glucose, and other needed chemicals from the blood to neurons and neuroglia.

Question 17

Where does cerebrospinal fluid continuously circulate through?

Answer 17

cavities in the brain and spinal cord and around the brain and spinal cord in the subarachnoid space (the space between the arachnoid mater and pia mater)

Question 18

Total CSF in adults?

Answer 18

80 to 150 mL

Question 19

What molecules are found in CSF?

Answer 19

CSF contains small amounts of glucose, proteins, lactic acid, urea, cations (Na+, K+, Ca2+, Mg2+), and anions (Cl− and HCO3−); it also contains some white blood cells.

Question 20

What are ventricles in relation to CSF?

Answer 20

CSF filled cavities in the brain

Question 21

How many ventricles are there?

Answer 21

1 lateral ventricle (per side) separated by membrane septum pellucidum and the third ventricle is a narrow slitlike cavity along the midline superior to the hypothalamus and between the right and left halves of the thalamus. The fourth ventricle lies between the brain stem and the cerebellum.

Question 22

3 main CSF functions?

Answer 22

mechanical protection, homeostatic function, circulation

Question 23

what is mechanical protection of the CSF?

Answer 23

CSF serves as a shock-absorbing medium that protects the delicate tissues of the brain and spinal cord from jolts that would otherwise cause them to hit the bony walls of the cranial cavity and vertebral canal. The fluid also buoys the brain so that it ‘floats’ in the cranial cavity.

Question 24

What is homeostatic function of CSF?

Answer 24

The pH of the CSF affects pulmonary ventilation and cerebral blood flow, which is important in maintaining homeostatic controls for brain tissue. CSF also serves as a transport system for polypeptide hormones secreted by hypothalamic neurons that act at remote sites in the brain.

Question 25

What is CSF's role in circulation?

Answer 25

CSF is a medium for minor exchange of nutrients and waste products between the blood and adjacent nervous tissue.

Question 26

Where is the majority of CSF produced?

Answer 26

Choroid plexuses (network of capillaries in the walls of ventricles), with epidymal cells around it joined by tight junctions which secrete substances flowing through the choroid plexus.

Question 27

What do ependymal cells surrounding the choroid plexus do?

Answer 27

Selected substances (mostly water) from the blood plasma, which are filtered from the capillaries, are secreted by the ependymal cells to produce the cerebrospinal fluid.

Question 28

what creates the blood-cerebrospinal barrier?

Answer 28

tight junctions between ependymal cells, materials entering CSF from choroid capillaries cannot leak between these cells; instead, they must pass through the ependymal cells.

Question 29

blood–cerebrospinal fluid barrier permeability ?

Answer 29

Semi-permeable: certain substances to enter the CSF but excludes others, protecting the brain and spinal cord from potentially harmful blood-borne substances.

Question 30

Where is CSF reabsorbed?

Answer 30

arachnoid villi (fingerlike projections in the arachnoid mater)

Question 31

The cerebral cortex has three main areas:

Answer 31

sensory, motor and association areas

Question 32

Sensory areas:

Answer 32

receive sensory information and are involved in perception, the conscious awareness of a sensation

Question 33

Motor areas:

Answer 33

control the execution of voluntary movements

Question 34

Association areas:

Answer 34

deal with more complex integrative functions such as memory, emotions, reasoning, will, judgement, personality traits, and intelligence

Question 35

Sensory areas are usually found:

Answer 35

behind central sulci (posterior)

Question 36

What is found in the forebrain?

Answer 36

superficial (cortex, corpus callosum, parieto-occipital sulcus, calcarine sulcus, primary visual corex), basal ganglia, diencephalon

Question 37

What is cortex?

Answer 37

grey matter thrown into ridges (gyri) and folds (sulci)

Question 38

Corpus callosum is what?

Answer 38

A white matter tract carrying information between the hemispheres

Question 39

what is the parieto-occipital sulcus?

Answer 39

a very deep sulcus that crosses the posterior part of the hemisphere and divides the internal occipital lobe from the parietal and internal temporal lobes

Question 40

What is the calcarine sulcus?

Answer 40

The calcarine sulcus (or calcarine fissure) is an anatomical landmark located at the caudal end of the medial surface of the brain of humans and other primates.

Question 41

Where is the primary visual cortex found? What is its role?

Answer 41

Centred on the calcarine sulcus in the occipital lobe (bottom front), receives visual information and is involved in visual perception

Question 42

Basal ganglia are found where in the forebrain?

Answer 42

buried deep within each hemisphere

Question 43

Diencephalon in the forebrain hold what?

Answer 43

The thalamus, hypothalamus, pituitary gland, third ventricle

Question 44

What does the thalamus do?

Answer 44

relays almost all sensory input to the cortex

Question 45

What does the hypothalamus do?

Answer 45

controls internal body functions and the autonomic nervous system

Question 46

Where is the pituitary gland and what is it controlled by?

Answer 46

attached and controlled by the hypothalamus (always torn off when brain is removed from the skull)

Question 47

What is in the midbrain?

Answer 47

Superior/inferior colliculi, cerebral aqueduct, cerebral peduncles

Question 48

What do the superior and inferior colliculi of the midbrain do?

Answer 48

found at roof of midbrain, minor role in controlling eye movements and movements related to auditory stimuli

Question 49

Cerebral aqueduct is found where?

Answer 49

narrow passage linking the 3rd and 4th ventricles (thick as a matchstick)

Question 50

What do cerebral peduncles do and what are they made up of (midbrain)?

Answer 50

carry info between cerebral cortex and the spinal chord (corticospinal fibres) and cortext to pons (corticopontine fibres). They are thick white matter tracts making up the floor of the midbrain

Question 51

What is found in the hindbrain?

Answer 51

cerebellum, pons, medulla, fourth ventricle