17.11 Human central nervous system | Human brain class 12

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irtisam's biology
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The brain is the most complex organ in the human body; the cerebral cortex (the outermost part of the brain and the largest part by volume) contains an estimated 15–33 billion neurons, each of which is connected to thousands of other neurons.

In total, around 100 billion neurons and 1,000 billion glial (support) cells make up the human brain. Our brain uses around 20 percent of our body’s total energy.

The brain is roughly split into four lobes:

Temporal lobe (green): important for processing sensory input and assigning it emotional meaning.

It is also involved in laying down long-term memories. Some aspects of language perception are also housed here.

Occipital lobe (purple): visual processing region of the brain, housing the visual cortex.

Parietal lobe (yellow): the parietal lobe integrates sensory information including touch, spatial awareness, and navigation.

Touch stimulation from the skin is ultimately sent to the parietal lobe. It also plays a part in language processing.

Frontal lobe (pink): positioned at the front of the brain, the frontal lobe contains the majority of dopamine-sensitive neurons and is involved in attention, reward, short-term memory, motivation, and planning.

Brain regions
Next, we will look at some specific brain regions in a little more detail:
Cerebellum: mostly involved in precise motor control, but also in language and attention. If the cerebellum is damaged, the primary symptom is disrupted motor control, known as ataxia.

Corpus callosum: a broad band of nerve fibers that join the left and right hemispheres. It is the largest white matter structure in the brain and allows the two hemispheres to communicate. Dyslexic children have smaller corpus callosums; left-handed people, ambidextrous people, and musicians typically have larger ones.

Medulla oblongata: extending below the skull, it is involved in involuntary functions, such as vomiting, breathing, sneezing, and maintaining the correct blood pressure.

Hypothalamus: sitting just above the brain stem and roughly the size of an almond, the hypothalamus secretes a number of neurohormones and influences body temperature control, thirst, and hunger.

Thalamus: positioned in the center of the brain, the thalamus receives sensory and motor input and relays it to the rest of the cerebral cortex. It is involved in the regulation of consciousness, sleep, awareness, and alertness.

Amygdala: two almond-shaped nuclei deep within the temporal lobe. They are involved in decision-making, memory, and emotional responses; particularly negative emotions.

Fsc biology lectures series by irtisamsbiology
4 سال پیش در تاریخ 1399/05/08 منتشر شده است.
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