SciOly Anatomy and Physiology: Nervous System

What are the two main parts of the nervous system?

The central nervous system (CNS) and the peripheral nervous system (PNS).

What does the central nervous system consist of?

The brain and spinal cord.

What is the peripheral nervous system composed of?

Nerves and ganglia not including the CNS.

How is the peripheral nervous system divided?

Into afferent (sensory) and efferent (motor) nervous systems.

What is the function of the afferent nervous system?

It is responsible for sensory input.

What are the two divisions of the efferent nervous system?

The autonomic and somatic nervous systems.

How does the autonomic nervous system operate?

It is controlled by the subconscious and happens automatically.

What type of muscle does the somatic nervous system affect?

Skeletal muscle, controlled by the conscious brain.

What are the two branches of the autonomic nervous system?

The sympathetic and parasympathetic nervous systems.

What is the role of the sympathetic nervous system?

It triggers the 'fight or flight' response during stress.

What does the parasympathetic nervous system control?

It regulates the body during times of rest.

What are the four main lobes of the brain?

Frontal lobe, parietal lobe, occipital lobe, and temporal lobe.

What is the primary function of the frontal lobe?

Responsible for conscious thought and decision-making.

What is the precentral gyrus also known as?

The somatomotor or primary motor cortex.

What does the motor homunculus represent?

The portions of the body controlled by the motor cortex.

At what age does the frontal lobe generally reach maturity?

Around 20 years old.

What is the primary role of the parietal lobe?

Associated with spatial processing and navigation abilities.

What does the occipital lobe process?

Visual images from the eyes.

What is the primary function of the temporal lobe?

Responsible for visual memory, object recognition, processing sound and smell, and understanding language.

What does the cerebrum control?

Perception, imagination, thought, judgment, and decision-making.

What is the primary function of the Cerebrum?

The Cerebrum controls perception, imagination, thought, judgement, and decision.

What percentage of the brain mass does the Cerebrum encompass?

About two-thirds of the brain mass.

What divides the two hemispheres of the Cerebrum?

The corpus callosum.

What are the two main lobes of the Cerebrum and their functions?

The occipital lobe processes vision, and the frontal lobe processes voluntary movement and planning.

What is the cerebral cortex and why is it referred to as gray matter?

The cerebral cortex is the outer layer of the brain that contains cell bodies and synapses but no myelin.

What are gyri and sulci in the context of the brain?

Gyri are the folded bulges of the brain, while sulci are the deep furrows or fissures between them.

What is the function of the medullary body in the Cerebrum?

The medullary body is the white matter of the cerebrum, consisting of myelinated axons.

What role do the basal ganglia play in the brain?

Basal ganglia are masses of gray matter involved in the control of voluntary muscle movements.

What is the primary function of the Cerebellum?

The Cerebellum controls balance, movement, coordination, attention, and language.

What involuntary functions does the Brain Stem control?

The Brain Stem controls respiration, digestion, circulation, sleep patterns, hunger and thirst, blood pressure, heart rhythms, and body temperature.

What are the three main parts of the Brain Stem?

The midbrain (mesencephalon), pons (part of the metencephalon), and medulla oblongata (myelencephalon).

What is the role of cranial nerves 3-12 located in the Brain Stem?

They send the main motor and sensory signals to the face and neck.

What is the function of the Pituitary Gland?

The Pituitary Gland controls the release of hormones throughout the body and is important in growth, especially during puberty.

What are the two main parts of the Diencephalon?

The thalamus and the hypothalamus.

What is the function of the Thalamus?

The Thalamus receives sensory impulses (except for smell) and channels them to appropriate regions of the cortex for interpretation.

How does the Hypothalamus contribute to homeostasis?

The Hypothalamus regulates body temperature and monitors food intake, water-salt balance, blood flow, sleep-wake cycle, and hormone activity.

What actions does the Hypothalamus initiate when the body is too hot or too cold?

It makes you sweat to lower temperature when too hot, and makes you shiver to increase temperature when too cold.

What role does the hypothalamus play in the body?

The hypothalamus regulates body temperature, food intake, water-salt balance, blood flow, sleep-wake cycle, hormone activity, and mediates emotional responses.

What structures are included in the limbic system and what are their functions?

The limbic system includes structures like the hippocampus, which processes short-term memory into long-term memory, and is important for memory, learning, and emotion.

What is the function of Broca's area?

Broca's area, located in the frontal lobe, is important for the production of speech.

What is the function of Wernicke's area?

Wernicke's area is responsible for the comprehension of language and the production of meaningful speech.

What is cerebrospinal fluid and its primary functions?

Cerebrospinal fluid is a colorless fluid that flows through the brain and spinal cord, acting as a barrier to prevent waste damage and maintain homeostasis.

What condition results from an excess of cerebrospinal fluid?

Hydrocephalus (or hydrocephaly) results from too much cerebrospinal fluid, causing swelling in the head.

What are the three types of fibers in the brain and their functions?

Commissural fibers conduct impulses between hemispheres, projection fibers conduct impulses in and out of cerebral hemispheres, and association fibers conduct impulses within the hemispheres.

What are the two main types of nerve cells in nervous tissue?

The two main types of nerve cells are neurons and neuroglia.

What are the primary functions of neuroglia?

Neuroglia maintain homeostasis, form myelin, support and protect neurons, supply nutrients and oxygen, insulate neurons, and remove pathogens and dead neurons.

What significant role do glial cells play in neurotransmission?

Recent research indicates that glial cells assist in synaptic transmission, regulate neurotransmitter clearance, and release gliotransmitters like ATP.

What was the historical belief about neuroglia's role in neurotransmission?

For over a century, it was believed that neuroglia did not play a role in neurotransmission, but this has been disproven.

What is the significance of astrocytes in neurotransmitter clearance?

Astrocytes are crucial for clearing neurotransmitters from the synaptic cleft, preventing toxic build-up and excitotoxicity.

What neurological diseases are glial cells thought to influence?

Glial cells are thought to play a role in many neurological diseases, including Alzheimer's disease.

What is the historical misconception about glial cells' features?

Glial cells were once thought to lack chemical synapses and the ability to release transmitters, being considered passive bystanders.

How did the understanding of glial cells change in the 21st century?

21st-century neuroscience recognizes that glial cells have effects on physiological processes and assist neurons in forming synaptic connections.

What is the role of the hippocampus in the limbic system?

The hippocampus processes short-term memory into long-term memory.

What is the relationship between the limbic system and emotions?

The limbic system mediates the effects of moods on behavior and influences internal changes in body function related to emotions.

What is the corpus callosum?

The corpus callosum is formed by commissural fibers that conduct impulses between the two hemispheres of the brain.

What are the two divisions of the nervous system where glial cells are found?

Glial cells are found in both the central nervous system (CNS) and the peripheral nervous system (PNS).

What types of glial cells are found in the central nervous system?

In the CNS, glial cells include oligodendrocytes, astrocytes, ependymal cells, and microglia.

What types of glial cells are found in the peripheral nervous system?

In the PNS, glial cells include Schwann cells and satellite cells.

What is the significance of the hypothalamus in relation to the autonomic nervous system?

The hypothalamus links the autonomic nervous system with other systems, regulating bodily functions and responses.

What role do astrocytes play in the nervous system?

Astrocytes support neurons, help form the blood-brain barrier, supply nutrients, and regulate the extracellular chemical environment.

What distinguishes oligodendrocytes from Schwann cells?

Oligodendrocytes myelinate multiple axons in the CNS, while Schwann cells myelinate only one axon at a time in the PNS.

What is the function of microglia in the CNS?

Microglia act as macrophages, protecting neurons from bacteria and viruses through phagocytosis.

What is the role of ependymal cells?

Ependymal cells line the ventricular walls, produce cerebrospinal fluid (CSF), and may act as neuronal stem cells.

How do Schwann cells contribute to nerve repair in the PNS?

Schwann cells regress to an earlier developmental state to encourage axon regrowth after injury.

What is the significance of the myelin sheath created by oligodendrocytes and Schwann cells?

The myelin sheath insulates nerve fibers and speeds up signal conduction.

What are the main types of glial cells in the CNS?

Astrocytes, oligodendrocytes, microglia, and ependymal cells.

What is the function of satellite cells in the PNS?

Satellite cells regulate the extracellular chemical environment around neurons.

What are the components of a nerve?

Nerves are made of neurons bound in bundles called fascicles, surrounded by endoneurium, perineurium, and epineurium.

What is the role of the spinal cord in the nervous system?

The spinal cord connects the brain to the rest of the body and is a long bundle of nerves.

How do neurons communicate with each other?

Neurons communicate through electrochemical waves that travel along axons and cross synapses.

What happens at the synapse during a nerve impulse?

Sodium and potassium ions are pumped across the synapse to the dendrite of another neuron.

What is the primary function of glial cells?

Glial cells support and protect neurons, playing crucial roles in the nervous system's development and repair.

What unique feature do oligodendrocyte precursor cells (OPCs) have?

OPCs have well-defined and functional synapses with major groups of neurons.

What is the difference in glial cell function between the CNS and PNS?

In the CNS, glial cells suppress repair, while in the PNS, they promote repair.

What is the significance of the blood-brain barrier?

The blood-brain barrier protects the brain from harmful substances while allowing essential nutrients to pass.

How do astrocytes regulate potassium ions?

Astrocytes help remove potassium ions to maintain the concentration gradient in the extracellular environment.

What is the role of the myelin sheath in nerve fibers?

The myelin sheath insulates nerve fibers and enhances the speed of electrical signal conduction.

What are the two major types of glial cells in the PNS?

Schwann cells and satellite cells.

What is the function of the endoneurium, perineurium, and epineurium?

These membranes surround and protect the bundles of nerve fibers.

What is the role of glial cells in synaptic plasticity?

Glial cells are crucial for processes such as synaptic plasticity and synaptogenesis.

What happens to Schwann cells after axonal injury?

They undergo regression to promote axon regrowth.

What is the primary role of the nerves in the body?

Nerves send messages and commands from the brain to the corresponding parts of the body.

What ions are pumped across the synapse in a nerve impulse?

Sodium and potassium ions.

What is the function of the eye?

The eye is the organ of vision, focusing light on the retina.

What are the two types of light-sensitive cells in the retina?

Rods and cones.

What is the role of cone cells in the retina?

Cone cells are sensitive to color and are located in the fovea.

What is the role of rod cells in the retina?

Rod cells are more sensitive to light and are responsible for peripheral and night vision.

What connects the eye to the brain?

The optic nerve.

What is the 'blind spot' in the eye?

The optic nerve, which is insensitive to light.

How does the brain process visual input from the eyes?

The brain combines input from both eyes into a three-dimensional image.

What compensates for the upside-down image on the retina?

The brain compensates to provide the right-side-up perception.

What happens to the eye in low light conditions?

A substance produced by rod cells increases sensitivity to detect dim light.

What does the iris do in strong light?

The iris contracts, reducing the size of the aperture that admits light.

What is the function of the ear?

The ear is the organ of hearing.

What structures transmit vibrations from the outer ear to the inner ear?

The malleus, incus, and stapes.

What is the cochlea?

The spiral-shaped chamber in the inner ear that reacts to vibrations.