Lecture four, Brain Anatomy

Question 1

What is ectoderm?

Answer 1

the outer of the three germ layers of the embryo (the other two being mesoderm and endoderm). Ectoderm gives rise to epidermis and neural tissue

Question 2

What are the germ layers?

Answer 2

The three layers of cells comprising the early embryo.

Question 3

What is the epidermis?

Answer 3

the outer layer of cells covering an organism, in particular

Question 4

What are Neural crest cells and what do they do?

Answer 4

Neural crest, group of embryonic cells that are pinched off during the formation of the neural tube (the precursor of the spinal cord) but that do not remain as a part of the central nervous system. The cells of the neural crest migrate to numerous locations in the body and contribute to the formation of diverse structures, mostly associated with the nervous system.

Neural crest cells form different tissues and
anatomical structures

additional information, not necessary, but illustrative:
The most conspicuous of the neural crest derivatives are the melanocytes, cells in the deep layers of the epidermis that contain pigment and are responsible for skin coloration. In the head region the neural crest cells contribute significantly to the formation of the facial bones. Odontoblasts, the cells that give rise to the dentine of the teeth, have their origin in the neural crest, as do many of the cranial nerve cells. The neural crest also contributes to the formation of the meningeal covering of the brain and is the source of Schwann cells, which surround and insulate nerve fibres in the peripheral nervous system. In addition to Schwann cells and melanocytes, the neural crest of the trunk region gives rise to paired chains of sympathetic nerve ganglia and to certain cells of the adrenal gland.

Question 5

Explain the terms dorsal and ventral

Answer 5

Dorsal or posterior refers to the back and ventral or anterior to the front (belly) side of the body.

Question 6

What is the dorsal root vs. ventral root, with what is it associated and what are dorsal root ganglions?

Answer 6

The dorsal (posterior)root allows sensory neurons to enter the spinal chord. The ventral or anterior root allows motor neurons to exit the spinal chord.

Along each dorsal root is small bulge called the dorsal root ganglion (spinal ganglion). Inside this ganglia are the cell bodies of the sensory neurons.

Dorsal and ventral roots fuse to form the spinal nerve.

Question 7

What are ganglions?

Answer 7

Greek word meaning: “encysted tumour on a tendon, anything gathered into a ball”

In neuroanatomy:
An encapsulated collection of nerve-cell bodies, located outside the brain and spinal cord.
Any of certain masses of gray matter in the brain, as the basal ganglia.

Question 8

Lateral, etymology

Answer 8

From Latin laterālis (“belonging to the side”), from latus (“side”).

(anatomy) Pertaining to the left or right of the body; further from the midline.

Question 9

What are Cajal-Retzius (CR) cells andwhat are they doing?

Answer 9

Cajal-Retzius neurons originate before any other neurons of the cortex are generated.

Question 10

Whats the pia mater?

Answer 10

often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. Pia mater is medieval Latin meaning “tender mother”. (german: Weiche Hirnhaut)

Question 11

Whats the radial glia cell?

Answer 11

Radial glial cells are bipolar-shaped cells that span the width of the cortex in the developing vertebrate central nervous system (CNS). and serve as primary progenitor cells capable of generating neurons, astrocytes, and oligodendrocytes.

Neurons climb up along the along the radial glia until reaching the C-Rcells.

Question 12

How is the cortex developed?

Answer 12

1. Radiale glia cellen in the “ventricular
   zone” form extensions outward
   2.Cajal-Retzius (CR) cells place
   themselves against the pia mater
   3.Neurons climb up along the along the radial glia until reaching the C-R-cells
2. C-R cells and pia mater are pushed outward

Question 13

What is apoptosis?

Answer 13

Cell death

Question 14

medial vs lateral

Answer 14

medial always more towards the midle of the body

Question 15

Rostral or anterior vs. caudal or posterior

Answer 15

rostral is towards the front of the neuraxis and caudal towards the tail/end.

Posterior and anterior are also used for dorsal and ventral, dont get confused!

Question 16

saggital plan

Answer 16

Perpendicular to the ground and parallel to the neuraxis, giving us sagittal sections. The midsagittal plane divides the brain into two symmetrical right and left halves.

Question 17

Ipsilateral

Answer 17

“same side of the body”

Question 18

Transverse plane

Answer 18

Transversely, like slicing a loaf of bread, giving us cross sections (also known as frontal sections when referring to the brain). A transverse cut to the middle of the brain would divide the brain into front and back halves

Question 19

(Horizontal plane)

Answer 19

Parallel to the ground, giving us horizontal sections. A parallel cut to the middle of the brain would result in cutting off the upper half of the brain.

Question 20

Recall that during embryonic development the brain is initially composed of three primary vesicles: Forebrain, Midbrain, and Hindbrain. These vesicles ultimately become five brain divisions: Telencephalon (cerebrum), Diencephalon, Mesencephalon (midbrain), Metencephalon (cerebellum and pons), and Myelencephalon.

Answer 20

http: //vanat.cvm.umn.edu/neurLab3/pages/EmbryoDivisions.html
http: //vanat.cvm.umn.edu/neurLab3/divisions.html

Forebrain = telencephalon = cerebrum
Little brain = metencephalon = cerebellum
Extended marrow = myelencephalon = medulla oblongata
Spinal cord
Thalamus and hypothalamus = diencephalon
Little brain = metencephalon = cerebellum

Question 21

Little brain = metencephalon = cerebellum

Answer 21

12 cranial nerves

31 pairs of spinal nerves

Question 22

Whart are the cervical nerves and the cervical plexus?

Answer 22

The cervical plexus is a network of nerve fibres that supplies innervation to some of the structures in the neck and trunk.

The spinal nerves C1 – C4 form the basis of the cervical plexus.

At each vertebral level, paired spinal nerves leave the spinal cord via the intervertebral foramina of the vertebral column.

Each nerve then divides into anterior and posterior nerve fibres. The cervical plexus begins as the anterior fibres of the spinal nerves C1, C2, C3 and C4.

These fibres combine with each other to form the branches of the cervical plexus.

http://teachmeanatomy.info/neck/nerves/cervical-plexus/

Question 23

What and where is the brachial plexus?

Answer 23

The brachial plexus is a network of nerve fibres that supplies the skin and musculature of the upper limb. It begins in the root of the neck, passes through the axilla, and enters the upper arm.

The plexus is formed by the anterior rami (divisions) of the cervical spinal nerves C5, C6, C7 and C8, and the first thoracic spinal nerve, T1.

Question 24

What is so special about the spinal chord from the lumber system downwards?

Answer 24

Spinal cord extends to
lumbar regions; below
this level the column is
filled with spinal fluid
(Cauda Equina), so it is possible to extract this liquid without damaging nerve cells

Question 25

What is the arachnoid mater?

Answer 25

The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord. The arachnoid mater is a derivative of the Neural crest mesectoderm in the embryo.

Question 26

What is the dura matter?

Answer 26

or dura, is a thick membrane that is the outermost of the three layers of the meninges that surround the brain and spinal cord. It is derived from mesoderm.

The other two meningeal layers are the arachnoid mater and the pia mater. The dura surrounds the brain and the spinal cord and is responsible for keeping in the cerebrospinal fluid.

Question 27

Which cranial nerves are associated with what senses (Also moto or sensory information)

Answer 27

1: smell (sensory)
2:vision (sensory)
3,4,6: eyes (motor)
5: jaw/face (motor/sensory)
7: face, taste (Motor/sensory)
8: hearing/balance (sensory)
9: throat/taste (Motor/sensory)
10: internal organs ( - )
11: neck (motor)
12: tongue (motor)

Question 28

What is the medulla oblongata? Tell me everything ;)

Answer 28

It is a reticular formation.
It is the continuation of the spinal cord within the skull, forming the lowest part of the brainstem.

Important set of nuclei a.o. involved with:
q Control of balance
q Control of heart and breathing
q Pain Modulation
q Sleep/wake cycles

Question 29

What is the Thalamus?

Answer 29

Its a relay station for transferring sensory information to cortex.

Question 30

And the Hypothalamus:

Answer 30

autonomic nervous system
for survival-fighting, feeding, fleeing, mating
Hormone secretion via pituitary

Question 31

What does the Diencephalon consists of?

Answer 31

The diencephalon consists of the thalamus, which directs information to and from the cerebral cortex, and the hypothalamus, which controls the endocrine system and modulates species-typical behaviors.

Question 32

What are the parts of the Telencephalon?

Answer 32

The telencephalon contains the cerebral cortex, the limbic system, and the basal ganglia. The cerebral cortex is organized into the frontal, parietal, temporal, and occipital lobes. The central sulcus divides the frontal lobe, which deals specifically with movement and the planning of movement, from the other three lobes, which deal primarily with perceiving and learning. The limbic system, which includes the limbic cortex, the hippocampus, and the amygdala, is involved in emotion, motivation, and learning. The basal ganglia participate in the control of movement.

Question 33

What are the parts of the hindbrain, and what are their functions? (Metencephalon)

Answer 33

The hindbrain, which surrounds the fourth ventricle, contains the cerebellum, the pons, and the medulla. The cerebellum plays an important role in integrating and coordinating movements. The pons contains some nuclei that are important in sleep and arousal. The medulla oblongata, too, is involved in sleep and arousal, but it also plays a role in control of movement and in control of vital functions such as heart rate, breathing, and blood pressure.

Question 34

What are the parts of the midbrain and what do they do?

Mesencephalon

Answer 34

The midbrain, which surrounds the cerebral aqueduct, consists of the tectum and the tegmentum. The tectum is involved in audition and the control of visual reflexes and reactions to moving stimuli. The tegmentum contains the reticular formation, which is important in sleep, arousal, and movement; the periaqueductal gray matter, which controls various species-typical behaviors; and the red nucleus and the substantia nigra, both parts of the motor system.

Question 35

What is the Myelencephalon and where is it?

Answer 35

The last part of the brain, connecting it to the spinal chors. Named Medulla Oblongata. The medulla contains the cardiac, respiratory, vomiting and vasomotor centers and therefore deals with the autonomic functions of breathing, heart rate and blood pressure.