Organization of the nervous system

• orientation in neuro

  A) rostral

  B) caudal

  C) axial

  D) para sagitall

  E) para median plane

  F) coronal or frontal

  
• •The midsagittal plane (often referred to simply as the sagittal plane ) goes through the midline and divides the brain into two symmetrical halves. Parasagittal planes are those parallel to the midsagittal plane; they divide the brain into asymmetrical right and left parts.

  
• •Coronal planes (also called frontal planes ) are perpendicular to the sagittal plane; they divide the brain into asymmetrical anterior and posterior parts.

  
• •Axial planes (also called transverse or horizontal planes ) are perpendicular to the long axis of the body; they divide the brain into asymmetrical superior and inferior parts. These terms are fairly straightforward and have the same meaning with respect to any part of the nervous system.
• •directional terms such as anterior, dorsal, and rostral change their meanings relative to each other in different parts of the nervous system.

  •The reason for this, is that walking upright necessitates a bend of about 80 degrees in going from the long axis of the spinal cord and brainstem to the long axis of the forebrain. This bend is a consequence of the cephalic flexure, which appears early in the embryological development of the nervous system and persists in the mature brain.

  
• •Dorsal-ventral terminology ignores the bend, as though we had a linear CNS and walked around on all fours like most other vertebrates, so the directional meaning of “dorsal” changes by 80 degrees at the midbrain-diencephalon junction. The terms anterior and superior, in contrast, retain a constant meaning relative to the normal upright orientation of the body as a whole.
• rostral means “toward the nose.”
• This means, for example, that the ventral surface of the spinal cord is also its anterior surface, but the ventral surface of the forebrain is its inferior surface. Rostral-caudal terminology may cause additional confusion. Anatomically, rostral means “toward the nose.” However, it also has a functional connotation for many (implying “toward the telencephalon”), so the posterior end of the cerebral hemispheres could be considered rostral to all parts of the diencephalon.
• Cephalic Flexure

  is a ventrally directed bend through the mesencephalon, and a ventral bulging and elongation of the prosencephalon.

  
• what planes

  A) inferior

  B) superior

  C) posterior

  D) anterior

  E) dorsal

  F) ventral

  G) ventral

  H) dorsal

  
• •The adult human brain weighs between 1,200 to 1,500 g and contains about one trillion cells.

  • It occupies a volume of about 1400 cc - approximately 2% of the total body weight, and receives 20% of the blood, oxygen, and calories supplied to the body.
• Neurons

  •Functions include

  •Receive and integrate incoming information/input from sensory receptors and other neurons.

  •Integrate information from various sources

  •Transmit information to other neurons and non-neural structures (muscles, organs, glands)

  
• what are these

  A) dendrite

  B) cell body

  C) axosomatic synapse

  D) axon

  E) axodendritic synapse

  F) axon colateral

  
• •Neurons in the nervous system exhibit wide diversity in size and shape. Multipolar, unipolar and bipolar

  
• •Common characteristics of neurones include a single cell body and branching processes which are receptive dendrites that possess synapses for receiving information. Dendrites in sensory neurons may specialize in detecting changes in the environment.

  
• •The axon, or nerve fiber, extends from the cell body and carries information away. Axons vary in length and may have collateral branches for distributing information.

  
• •Nerve terminals (presynaptic endings) occur at the end of axons for transferring information. In motor neurons, axonal endings may be specialized, such as the neuromuscular junction.
• •Neuronal Information Transmission:

  •Information is coded and distributed in neurons through changes in electrical charge.

  •Neuron cell membrane is polarized, creating a membrane potential.

  •Resting potential is around 60–70 mV, with the inside of the cell being negative.
• •Action Potential:

  •Neuron stimulation above threshold leads to a brief reversal of membrane potential called action potential.

  •Action potentials propagate down the axon and invade nerve terminals.
• •Synaptic Transmission:

  •Most synapses use chemical transmission.

  •Action potential invasion triggers release of neurotransmitters stored in synaptic vesicles.

  •Neurotransmitters diffuse across the synaptic gap to bind with receptors on the postsynaptic cell.
• •Neurotransmitter Effects:

  •Binding induces changes in postsynaptic membrane potential.

  •Changes may depolarize, moving towards the threshold for action potentials, or hyperpolarize, stabilizing the cell.
• neuroglia

  •Outnumber neurons by about ten times in the nervous system.

  •Do not participate directly in information processing like neurons.

  
• neuroglia

  •Functions include

  •Normal Functioning: Neuroglial cells play a vital role in maintaining the normal functioning of the nervous system. They complement neurons to ensure efficient neural communication.
• neuroglia what is what

  A) dendrite

  B) cell body

  C) axon

  D) myelin

  E) node of ranvier

  
• One type of glial cell (the oligodendrocyte) is responsible for the production of myelin, a structure high in lipoprotein that ensheathes many axons and greatly increases the speed of conduction of action potentials.

  •Oligodendrocytes in CNS, Schwann cells in PNS

  •Includes oligodendrocytes, astrocytes, ependymal cells, and microglial cells

  
• •The PNS consists of nerve fibres that transmit specific sensory and motor information to the CNS.

  •The CNS is housed within the bony structures of the vertebral canal and skull for protection
• •Central nervous system (CNS)– brain and the spinal cord
• •Peripheral nervous system (PNS)– cranial nerves, the spinal nerves, the ganglia associated with the cranial and spinal nerves , and the peripheral receptor organs.
• •Autonomic nervous system (ANS) – part of the nervous system involved mainly in the regulation of visceral function (located partly within the CNS and partly within PNS)
• Central nervous system (CNS)

  A) forebrain

  B) prosencephalon

  C) midbrain

  D) mesencephalon

  E) hindbrain

  F) rhombencephalon

  G) telencephalon

  H) diencephalon

  I) mesencephalon

  J) metencephalon

  K) myelencephalon

  L) cerebral hemispheres

  M) Thalamus

  N) hypothalamus

  O) midbrain

  P) pons

  Q) cerebellum

  R) medulla

  S) lateral ventricles

  T) third ventricle

  U) cerebral aqueduct

  V) upper part of 4th ventricle

  W) lower part of 4th ventricle

  
• Central nervous system (CNS)

  •The brain and the spinal cord arise in early development from the neural tube, which expands in front of the embryo to form the three primary brain divisions: the prosencephalon, mesencephalon and rhombencephalon

  •These three vesicles further differentiate into five subdivisions: telencephalon, diencephalon, mesencephalon, metencephalon, and the myelencephalon

  
• Central nervous system

  The CNS consists of the brain and spinal cord and accomplishes complex functions such as storage of experience (memory), development of ideas (thinking) as well as emotions, and enables the rapid adjustment of the whole organism to extrinsic and intrinsic changes in the external environment and within the body.

  
• Central nervous system

  A) spinal cord

  B) cerebellum

  C) medulla oblaganta

  D) pons

  E) midbrain

  
• Central nervous system

  A) cerebellum

  B) iv ventricle

  C) mesencephalon

  D) myelencephalon

  E) pons

  
• Central nervous system

  A) cranial nerves

  B) cerebrum

  C) cerebellum

  D) brainstem

  E) spinal cord

  F) spinal nerves

  
• Brain and Brainstem

  A) cerebral hemispheres

  B) cerebrum

  C) diencephalon

  D) Thalamus

  E) hypothalamus

  F) brainstem

  G) midbrain

  H) pons

  I) medulla

  J) cerebellum

  K) spinal cord

  L) midbrain-diencephalic junction

  M) pontomesencephalic junction

  N) pontomedullary junction

  O) cervicomedullary junction

  
• Cerebrum

  Central sulcus separates frontal lobe and parietal lobe of cerebrum

  
• Cerebrum

  Lateral sulcus separates temporal from the superior lobes

  
• Cerebrum

  Parietooccipital sulcus separates occipital lobe from frontal and parietal

  
• Cerebrum

  Houses nuclei for CN I and II (olfactory and optic nerves)