Development and organization of the nervous system

CNS

Brain (perception and cognition) and Spinal Cord

PNS division I

Somatic / Autonomic (Sensory in/motor out)

Somatic

Controls voluntary actions like raising a hand or walking (PNS). Have one area of skin that correlates with with spinal nerves

Autonomic

Controls involuntary actions like breathing, heart beat (PNS)

Somantic nervous system division

(PNS - Somatic) Afferent nerves - 5 senses. Efferent nerves - skeletal motor (moving)

Autonomic nervous system division

(PNS-automatic) afferent nerves (sensory information from internal organs) and efferent nerves (carries motor information out that controls heartbeat, breathing),

Efferent Nerves in Autonomic nervous system

(PNS - Autonomic - efferent) divides into sympathetic - shifting of blood, when activities system is either fight or flight, and parasympathetic - Resting and Digesting state

Potency

the ability to develop into different types of cells

Totipotent

The ablilty of cells to be extracted and implanted to form another success for pregnancy.

Pluripotent / Multipotent

the Ability of cells to turn into a couple of other things

Unipotent

The ability to only turn into one thing

Zygote

egg and sperm meet, about 8-10 days time in between fertilization and implantation.

Morula

3 days into devolvement. Group of 16-32 cells that are virtually identical. CELLS ARE TATIPONENT

blustula

fluid filled cavity fills morula. Cells on the outside are destined to be support cells, and small group too the side are destined to be enbronyic stem cells (inner cell mass). Should be implanted in uterine lining now. CELLS ARE PLURIPONENT

pluriponent

embryonic stem cells - cells that become the future you

Blastocyst

Ending position of embryo in germinal stage, baby is compacted into a disc.

Multiponent

Cells that are able to become one of a few things; but not everything

Gastrulation

-2 to 3 weeks into pregnancy. Cells push against each other and submerge creating 3 layers. Cells are said to be MULTIPONENT

Gastrulation top layer

Ectoderm -Skin and Nervous system CELLS ARE MULTIPONENT

Gastrulation middle layer

Mesoderm - Muscles and Skeletons CELLS ARE MULTIPONENT

Gastrulation bottom layer

Endoderm - internal organs CELLS ARE MULTIPONENT

Neurulation - Ectoderm

• HappeCells in the middle of the ectoderm are destined to be the foundation of the nervous system. Forms into a neural plate and then cells on the edge of the plate begin to curl up and form the neural tube

Neural tube

CNS brains and spinal cord, filled with fluid cavities that turn into ventricles and the spinal cavity. CELLS ARE UNIPOTENT.

Cells that don’t make it into the neural tube

squeezed out on top of neural tube, becomes neural crest PNS

Cells around the neural tube

Somites - mesoderm, middle layer. Cells around the neural tube turn into bone that surrounds the CNS.

Neurulation

Point at which nervous system develops, at the end cells are unipotent

neural proliferation

happens from about 3 week to 40 week. Neural tube creates about 4000 cells per second to change the shape of the Neural tube. End of the tube enlarges and the bottom narrows to become spinal cord. 3 Bumps into 5 Bumps (5 major divisions of the brain).

Neural Migration and Aggregation

neurons move from middle to the edge of the neural tube to begin forming there sutures via cell vel crows (sticky protein, if they match cells group). Then they “aggregate” (group) and form structures

Neural Stem cells

Radial glial cells

radical Neural cell migration

cells climb the rope to the outside of the neural tube

Tangential neural cell migration

cells travel down the and around the neural tube to achieve the outside

Axon Growth and Synapse formation

Once positioned neurons extend figures that smell chemicals to call. These figures will ultimately become axon dendrites. “Growing tip” - called growth cone.

Synapse Refinement

Nuerial cells call way to many cells over so they have to go through a process of getting rid of them. Cells release chemicals and if they receive one back they get to become a match. Cells that don’t match die.

Anterior/rostral

Towards the front nose

posterior/caudal

towards the back/tail

dorsal/superior

towards the top

ventral/inferior

towards the bottom

Medial

towards the middle

lateral

towards the side

Structures on the same side

ipsilateral

structures on opposite sides

contralateral

IN HUMANS Anatomical direction for head

(looking at human from the side) anterior - pointing to face, dorsal - pointing to top of the head (hair), posterior - pointing to back of the head/neck, ventral - pointing to the feet

IN HUMANS Anatomical direction for body

(looking at human from the side) anterior - pointing to the top of the head (hair), ventral - pointing to the chest, posterior - pointing to the ground, dorsal - pointing to back.

IN HUMANS MEDIAL

towards spinal cord

IN HUMANS LATERAL

towards neck

Sagittal plane

midsagittal cut, splits brain right in half

Horizontal place

cuts brain in half but horizontally. at about the ears

Frontal plane

cuts brain in half from the vertical way (like beats headphones).

Cross section

ONLY in spinal cord at an angle

The cerebrum

top majority of the brain, Biggest part consists of telencephalon. Split into 2 hemispheres that receive sensory imput and control motor output to the opposite sides of the body.

Corpus Callosum

connects two hemispheres of the brain

cerebellum

Motor control center - “lets do it well”

brain stem/spinal cord

PNS - performs basic functions like heart rate, blood pressure, and breathing. Main way information get out. 31 pairs of nerves that control different movements. (top nerves control arms and fingers, bottom ones control feet and legs)

Dorsal root

brings sensory information to the brain

ventral root

brings motor information out,

Brain blood barrier

CNS - blood will kill brain, but it needs it to function. enters through tight capillaries. Brain floats in blood that has been scrubbed of nutrients

Autonomic nervous system spinal nerves

middle spinal nerves are for fight or flight and the end and beginning of spinal nervous are for rest and digest.

Cranial nerves

information goes straight to the brain, touch on face, head or neck. hearing, seeing, smell ect.