Nervous System part 1

Nervous System Divisions

• The motor division of the nervous system is divided into the somatic nervous system and the autonomic nervous system.
• The somatic nervous system controls voluntary movement, while the autonomic nervous system controls involuntary functions like heart rate and digestion.

Neuron Structure and Function

• Dendrites receive signals from other neurons and transmit them towards the cell body.
• Schwann cells provide insulation for axons in the peripheral nervous system, forming the myelin sheath.
• Neurons communicate with each other through neurotransmitters, chemicals released at synapses (gaps between neurons).
• The cell body of a neuron contains the nucleus and other organelles, responsible for the neuron's metabolic functions.
• Nodes of Ranvier are gaps in the myelin sheath, essential for rapid impulse transmission.
• Gray matter in the nervous system is primarily composed of neuron cell bodies.
• Axons are typically longer and thinner than dendrites, and transmit impulses away from the cell body.
• Damage to the neuron's cell body leads to its death.

Nervous System Organization

• The nervous system is divided into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS includes the brain and spinal cord, responsible for processing and coordinating information.
• The PNS connects the CNS to the rest of the body, carrying information to and from the CNS.
• The sensory division of the PNS receives information from the body and transmits it to the CNS.
• The autonomic nervous system is responsible for immediate responses.

Nervous Tissue and Cells

• Neurons are the primary cells in nervous tissue, responsible for transmitting information.
• The endocrine system uses hormones to communicate, while the nervous system uses neurotransmitters for faster communication.
• The central nervous system includes the brain and spinal cord.
• The nervous system's primary function is to receive, process, and transmit information to control body functions.
• The nervous and endocrine systems work together to maintain homeostasis in the body.

Nervous Tissue Characteristics and Structures

• Nervous tissue is highly specialized and excitable.
• Receptors in the peripheral nervous system are specialized structures that detect stimuli from the environment.
• The myelin sheath insulates axons, allowing for faster and more efficient impulse transmission.
• Nodes of Ranvier are unmyelinated gaps between segments of myelin, facilitating rapid nerve impulse conduction.
• Schwann cells are responsible for myelination in the peripheral nervous system.
• Dendrites receive signals from other neurons and transmit them towards the cell body.

Neuron Physiology

• The resting potential of a neuron is the electrical potential across the cell membrane when the neuron is at rest.
• Neuroglial cells support and protect neurons, aiding in their function.
• Neuroglial cells continue to replicate throughout a person's life.
• During the action potential, a rapid change in electrical potential occurs across the neuron's membrane, allowing for the transmission of nerve impulses.
• Irritability and conductivity are properties of neurons that allow them to respond to stimuli and conduct nerve impulses.

Central Nervous System Structures and Functions

• Blood vessels are primarily located in the area of blood vessels in the CNS.
• Astrocytes are star-shaped glial cells in the CNS with various functions, including maintaining the blood-brain barrier and providing support for neurons.
• Oligodendrocytes are glial cells in the CNS responsible for forming myelin sheaths around axons.
• The blood-brain barrier protects the brain from harmful substances in the bloodstream.
• Lipid-soluble substances can quickly cross the blood-brain barrier.

Synaptic Transmission

• Synaptic vesicles store and release neurotransmitters.
• The space between neurons is called the synaptic cleft.
• Acetylcholine, norepinephrine, and dopamine are neurotransmitters involved in synaptic transmission.

Blood-Brain Barrier Composition

• The blood-brain barrier is a protective barrier made of tight junctions between endothelial cells of blood vessels and surrounding astrocytic foot processes.
• Nerve impulses are transmitted through the release of neurotransmitters at synapses.
• The blood-brain barrier is composed of specialized endothelial cells, a basement membrane, and astrocytic foot processes.