Introduction to Neurophysiology Flashcards
Describe the nervous system
Nervous system is a well-organized system of communication that allows the individual to interact with his external environment.
● It is also a system of integration that coordinates functions of various internal organ systems of the body.
What makes the nervous system unique?
The nervous system is unique because it affects every other system of the body.
The human brain is a network of more than __________ nerve cells
100 billion
List the subdivisions of the nervous system
The nervous system is anatomically subdivided into the central nervous system (CNS) and peripheral nervous system (PNS).
The central nervous system comprises of:
the brain and the spinal cord
The peripheral nervous system comprises:
It comprises the peripheral nerves originating from the brainstem and spinal cord (cranial and spinal nerves, respectively), as well as specialized clusters of neurons referred to as ganglia
The PNS is divided into two functional components:
the ________ and ________ divisions.
Somatic and autonomic
List the features of the somatic nervous system
This system controls all voluntary actions (i.e., intentional movements but not reflexive ones).
–All “processing” occurs in the brain and therefore at a conscious level.
–Anatomically consists of an AFFERENT loop, comprising the sensory nerves leading to
the brain, and an EFFERENT loop, comprising motor nerves from the brain to the muscles.
State the features of the autonomic nervous system
–This system controls all involuntary actions (e.g., reflexes, respiration) by regulating the functions of viscera, smooth muscles, exocrine and endocrine glands.
–It comprises sensory and motor neurons running between the brain and various internal organs such as the heart, lungs, etc.
The autonomic nervous system is further subdivided into which three systems?
It is further divided into the parasympathetic, sympathetic, and enteric nervous systems.
Which two systems ensure the protection of the brain?
This is ensured by two separate systems, the blood-brain barrier (BBB) and blood-CSF barriers.
Describe the blood-brain barrier
It is composed of endothelial cells packed tightly together to form tight junctions that prevent passage of most molecules
What is the name of the structure that reinforces the blood-brain barrier?
An underlying basement membrane and specialized glial cells (astrocytes), which project processes (pedicels) that attach to the walls of the capillary, reinforce this barrier.
List 4 features of circumventricular organs
• They are vascular brain structures around the ventricles.
●No blood brain barrier present.
●They allow the CNS to communicate with the blood stream.
●Some are secretory whilst others are sensory.
Name any 4 circumventricular organs that you can remember.
• Area Postrema
●OVLT (Organum Vasculosum of the lamina terminalis)
●Subfornical organ(SFO)
●Median Eminence of Hypothalamus
Area Postrema is at the _____ end of 4th ventricle in medulla.
Caudal
Why is Area Postrema referred to as Chemoreceptor Trigger zone?
This is because chemo agents affect this area.
What sends signals to the vomiting center in the medulla?
Area Postrema
What does the acronym OVLT refer to?
Organum Vasculosum of the lamina terminalis
Two facts about OVLT
It is located in the anterior wall of the third ventricle.
●It contains Osmosensory neurons.
Describe the Subfornical organ
•Located in the anterior wall of third ventricle.
●Responds to many circulating substances.
●Responds to Angiotensin 2
●Projects to other brain areas
What are the functions of the median eminence of hypothalamus
• Releases hormones into vascular system to Pituitary.
●Allows Hypothalamus to regulate Pituitary.
Give two examples of areas without the Blood-brain barrier (BBB)
Other brain areas without BBB include:
●Posterior Pituitary gland.
●Pineal gland.
What is Cerebrospinal Fluid (CSF) ?
Cerebrospinal fluid (CSF) is a clear, colorless fluid that normally contains none or few cells, a small amount of protein, and a moderate amount of glucose
The blood-CSF barrier is composed of ________ cells of the highly vascular ________ plexus located within the ventricles
Epithelial; choroid
CSF is secreted by the choroid plexus within the ______,_______, and ______ ventricles of the brain.
Lateral; third; fourth
What is hydrocephalus?
It is a dilation of the cerebral ventricular system due to either:
-overproduction of CSF
-an obstruction to the flow of CSF or
- failure of reabsorption of CSF.
