Cerebral Circulation and Brain Structures Quiz

Study Notes

Cerebral Circulation

The brain receives 750 ml of blood per minute.
The brain uses 20% of total O2 uptake.
Glucose is the brain's only source of energy.

Meninges and Ventricles

The brain has a set of communicating cavities within it called ventricles.
Ventricles produce, transport, and remove cerebrospinal fluid (CSF).
CSF is a watery fluid that bathes the CNS, surrounds and cushions the spinal cord and brain, and has three main functions: protection, buoyancy, and chemical stability.
CSF is lined by ependymal cells, which form the choroid plexus.

Ventricular System Diseases

Hydrocephalus and Ventriculitis can occur due to infection from a brain surgery.

Spinal Cord

The spinal cord has three main functions: sending motor commands from the brain to the body, sending sensory information from the body to the brain, and coordinating reflexes.
The spinal cord extends from the medulla oblongata of the brain stem at the level of the foramen magnum.
Reflex arcs allow the body to respond to sensory information without waiting for input from the brain.
In adults, the spinal cord tapers to an end, termed the conus medullaris, at the second lumbar vertebra level.
Past the conus medullaris, a bundle of spinal roots extends, termed the cauda equina.
The cauda equina and the subarachnoid space continue until S2, which is the target location for a lumbar puncture (spinal tap).

Blood-Brain Barrier (BBB)

The BBB is a highly selective semi-permeable membrane located between the blood and brain interstitium.
The main function of the BBB is brain homeostasis.
Gases such as carbon dioxide and oxygen, as well as lipophilic molecules with a molecular weight under 400 Da, can freely diffuse across the BBB.
Astrocytes play a significant role in stabilizing and maintaining BBB integrity.
The BBB is composed of cerebral capillary wall endothelial cells (ECs) held together via tight junctions (TJs), surrounded by pericytes, astrocytes, and basal lamina.

Impulse Transmission

Neuroglia (glial cells) provide nourishment, protection, and basic support to neurons.
Neuroglia cells may be a source of tumor in the NS.
Neuroglia are important in the transmission of impulses.
Mature glial cells retain the ability to divide by undergoing mitosis.
Neurons do not conduct nerve impulses.
Human brain has generally roughly equal numbers of neurons and neuroglia.
Having a relatively high number of neuroglia is associated with higher intelligence.
An increase in the ratio of neuroglia to neurons is associated with greater intelligence in species.

Neuron Function

Neurons transmit impulses through electrical signals that convey information along a neuron.
The three processes involved in nerve impulse transmission are polarization, depolarization, and repolarization.

Neurogenesis

Formation of new neurons by cell division may occur in a mature human brain, but only to a limited extent.
The average brain contains about 100 billion brain cells, most of which were formed before birth.
The hippocampus appears to be where much of the neurogenesis activity takes place.
Research has found that the hippocampus can produce anywhere from 700 to 1,500 new neurons each day.

Brain Health

120 to 150 minutes of moderate-intensity exercise per week is good for the brain.

Types of Neurons

Neurons can be classified functionally based on the direction in which they carry nerve impulses.
There are three main types of neurons: sensory (afferent), motor (efferent), and interneurons.

The Five Basic Senses

The five basic senses are sight, taste, touch, hearing, and smell.
Perception is the ability to recognize objects with the use of the special senses.
Sense of sight is mediated by photoreceptors (rods and cones).
Sense of taste is mediated by gustatory receptors.
Sense of touch is mediated by mechanoreceptors.
Sense of hearing is mediated by mechanoreceptors.
Sense of smell is mediated by olfactory receptors.

Sensory Receptors

Sensory receptors are specialized areas in a sensory neuron that detect specific stimuli.
Examples of sensory receptors include:
- Touch/tactile receptors
- Chemoreceptors
- Nociceptors
- Proprioceptors
- Thermoreceptors
- Mechanoreceptors
- Hair cells
- Free nerve endings

Description

Test your knowledge on cerebral circulation and brain structures with this quiz. Learn about the amount of blood and oxygen the brain receives, the importance of glucose as the brain's energy source, and the functions of the meninges, ventricles, and cerebrospinal fluid (CSF).