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By the end of this section, you will be able to:
  • Name the major regions of the adult brain
  • Describe the connections between the cerebrum and brain stem through the diencephalon, and from those regions into the spinal cord
  • Recognize the complex connections within the subcortical structures of the basal nuclei
  • Explain the arrangement of gray and white matter in the spinal cord

The brain and the spinal cord are the central nervous system, and they represent the main organs of the nervous system. The spinal cord is a single structure, whereas the adult brain is described in terms of four major regions: the cerebrum, the diencephalon, the brain stem, and the cerebellum. A person’s conscious experiences are based on neural activity in the brain. The regulation of homeostasis is governed by a specialized region in the brain. The coordination of reflexes depends on the integration of sensory and motor pathways in the spinal cord.

The cerebrum

The iconic gray mantle of the human brain, which appears to make up most of the mass of the brain, is the cerebrum    ( [link] ). The wrinkled portion is the cerebral cortex    , and the rest of the structure is beneath that outer covering. There is a large separation between the two sides of the cerebrum called the longitudinal fissure    . It separates the cerebrum into two distinct halves, a right and left cerebral hemisphere    . Deep within the cerebrum, the white matter of the corpus callosum    provides the major pathway for communication between the two hemispheres of the cerebral cortex.

The cerebrum

This figure shows the lateral view on the left panel and anterior view on the right panel of the brain. The major parts including the cerebrum are labeled.
The cerebrum is a large component of the CNS in humans, and the most obvious aspect of it is the folded surface called the cerebral cortex.

Many of the higher neurological functions, such as memory, emotion, and consciousness, are the result of cerebral function. The complexity of the cerebrum is different across vertebrate species. The cerebrum of the most primitive vertebrates is not much more than the connection for the sense of smell. In mammals, the cerebrum comprises the outer gray matter that is the cortex (from the Latin word meaning “bark of a tree”) and several deep nuclei that belong to three important functional groups. The basal nuclei    are responsible for cognitive processing, the most important function being that associated with planning movements. The basal forebrain    contains nuclei that are important in learning and memory. The limbic cortex    is the region of the cerebral cortex that is part of the limbic system    , a collection of structures involved in emotion, memory, and behavior.

Cerebral cortex

The cerebrum is covered by a continuous layer of gray matter that wraps around either side of the forebrain—the cerebral cortex. This thin, extensive region of wrinkled gray matter is responsible for the higher functions of the nervous system. A gyrus    (plural = gyri) is the ridge of one of those wrinkles, and a sulcus    (plural = sulci) is the groove between two gyri. The pattern of these folds of tissue indicates specific regions of the cerebral cortex.

The head is limited by the size of the birth canal, and the brain must fit inside the cranial cavity of the skull. Extensive folding in the cerebral cortex enables more gray matter to fit into this limited space. If the gray matter of the cortex were peeled off of the cerebrum and laid out flat, its surface area would be roughly equal to one square meter.

Questions & Answers

There was this time when the teacher is explaining about something that involves calculating.When the teacher calculate that (2×4)-(1×-3)=11.I was confused and think that the answer is wrong, so I asked the teacher.Then,I realized I calculate wrongly and then my head feels hot. Why?
Dicky Reply
I mean... (2 x 4)- (1 x -3) = 11
But since I don't really care about it. My head slowly goes back to normal.
blood is unique it is the only flueid tissue in the body
this is fascinating
for real
what is blood
sujon Reply
lol. the red substance in your body. that circulates food nutrients and oxygen
Blood is composed of plasma and formed elements. The plasma is about 55% of blood and is about 80-90% water usually. The other 20-10% accounts for solutes such as ions, nutrients, gases, and hormones.
Blood is a fluid type of connective tissue and it's formed elements (cells) include RBC, WBC, and plalets.
what is sasamoid bone?
hafeez Reply
how many types of bone on the base of shape
i want join the conversation
juwar Reply
feel free to do so
where are you from ?
hi what's up
well hello
Im from kashmir,but I'm studying in punjab
I'm studying pharmacy at JUST University in jordan
so am i emad 😅
I am Javed Ali
hello i am hafeez from gilgit
explain the mechanism(release and control) of hormonal interplay for fluid and electrolyte.
Cassie Reply
There are three main ways in which hormones may be released. Humoral stimulus - occurs when their is an inbalance in electrolytes in the body. Neural stimulus - occurs when autonomic nerve fibers stimulate glands to release hormones.
Hormonal stimulus - occurs when a hormone causes another hormone to be released from another gland.
what are the main pumps found in the cell membrane
pauline Reply
sodium potassium pump
Differences between ligaments and catilage
joy Reply
differences between catilage and ligaments
Both are different types of connective tissues. Second difference is that cartilage contains chondroblasts rather than fibroblasts. Their is also slight differences on their extracrullar matrix. For ex, cartilages tend to contain more collagen than tendons and ligaments.
Both types of connective tissue also function differently. Ligaments connect bone to bone, while cartilage have a variety of function like cushioning bones and giving structural support like on the nose and ears.
explain the causes of the refractory period of a nerve fiber
Sophia Reply
Refractory period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation. Brief pause in stimulus or excitation.
To add on, the brief pause is produced because of the event of establishing a resting membrane potential that needs to be produced before depolarization (another action potential) can occur again.
The refractory period also gives a chance for neurotransmitters to be replenished on the axon terminal.
what is hypoxia
Akas Reply
I guess it's low supply the oxygen to the tissues
A condition in which tissues (especially the blood) are deprived of an adequate supply of oxygen
hanifa pia uko hapa
Hypoxia is the lack of oxygen concentration in the blood. Therefore, tissues will receive a low concentration of oxygen. Usually our bodies respond to Hypoxia by stimulating erythropoiesis in red bone marrow.
hypoxia is the lack of oxygen in blood absolutely.
hypoxia: is a condition in wich the concentration of oxygen goes down in tissue or all over the body but the low concentration of oxygen in blood is called hypoxiemia.
where is present Glenoid Cavity ?
A- Reply
what is the muscular tissue
Md Reply
muscular tissue is a type of tissue that provide to help in cotraction to aur body.
What's the difference in epithelial, connective, muscular and muscle tissue
and it's similarities
what is limb bone
Akshu Reply
this are bone attaching or joining to the axial bone.axial bone including skull,vertebrate and ribcage
how many bones make up the skull?
22 bones
where is present Glenoid cavity ?
how many bone in skull
almost there are 8 bones in skull
Explain the stages of mitosis and cell division
Bella Reply
Bella, this is a very long process to detail by text. However, to keep it brief, mitosis has four phases in order: prophase, metaphase, anaphase, and telophase which sometimes followed by cytokinesis. Note that some cells do not always do the cytokinesis phase.
As a result, some of the cells in the body are multinuclear (osteoclasts for ex).
explain further
difference between mitosis and meosis
In mitosis, two genetically exact daughter cells (somatic cells) are produced and they are diploid. In meiosis, four genetically unique cells (gametes) are produced and they are haploid.
Meiosis only occurs in reproductive organs. Mitosis is a type of asexual reproduction and is involved in tissue growth and regeneration(repair).
mitosis > Diploid to Diploid meiosis > Diploid to Haploid
systems of human body
Udezue Reply

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