The Nervous System:

Neuromuscular Junction

• Junction between a terminal nerve ending and skeletal muscle

Peripheral Nervous System:

• Peripheral Nervous System:

  • Made up by the:

    • Cranial Nerves

    • Spinal Nerves

    • Ganglia

    • Enteric Plexuses in Small Intestine

    • Sensory Receptors in Skin

  • Neural tissue outside the Central Nervous System ( CNS)

  • Afferent division brings sensory information from receptors (one sub-division)

  • Everything that is outside

  • The efferent division carries motor commands to the effector (another sub-division)

  • The efferent division includes the somatic nervous system and the automatic nervous system (which has two more connections)

  • Nothing gets to the CNS unless it passes through the PNS

• Central Nervous System:

  • Made up of the brain and spinal cord

  • Is the information-processing aspect of the nervous system

  • Includes things like memory, earning, intelligence, speech, and any actions involved with the brain

• Afferent System:

  • Afferent neurons carry information from sensory receptors of the skin and other organs to the CNS ( i.e., brain and spinal cord)

  • Efferent neurons carry motor information away from the CNS to the muscles and glands of the body

• Autonomic System:

  • A component of the PNS that regulates involuntary physiologic processes including heart rate, blood pressure, preparation, digestion, and sexual arousal

• Cell Body:

  • Also called the soma

• Action Potential:

  • Another name for impulse

• Node of Ranvier:

  • Is characterized by short specialized regions in the axonal membrane that are not insulated by myelin

  • Gaps in the myelin sheath that allow electrical impulses to travel quickly down axons

• Nerve Impulse:

  • An electrical signal that travels along a nerve fiber in response to stimulus and serves to transmit a record of sensation from a receptor or an instruction to act to an effector

• What is the Myelin Sheath made of?:

  • Mainly composed of a high proportion of lipids (fatty substances) and a smaller amount of proteins, essentially acting as an insulating layer around nerve fibers, allowing for rapid electrical signal transmission

• What is a Neurotransmitter?:

  • It is a chemical messenger that carries signals between nerve cells located in the brain and the nervous system

• Neurotransmitter’s Functions:

  • Adrenergic synapses release norepinephrine (NE)

  • Other important neurotransmitters:

    • Dopamine

    • Serotonin

    • GABA ( Gamma Aminobutryruc Acid)

• Somatic Nervous System:

  • Part of the PNS that controls voluntary muscle movements, allowing control over body movements like walking, lifting, or typing by sending signals from the brain to the skeletal muscles

• The 12 Cranial Nerves:

  • Optic Nerve (Cranial Nerve 2):

    • Carries visual information from special receptors in the eyes

  • Trigeminal Nerve (Cranial Nerve 5):

    • Missed nerves with ophthalmic, maxillary, and mandibular branches

  • Abducens Nerve (Cranial Nerve 6):

    • Innervates the lateral rectus muscle

  • Facial Nerve (Cranial Nerve 7):

    • Mixed nerve that controls muscles of the face and scalp

    • Provides pressure sensations over the face

    • Receives taste info from the tongue

  • Vestibulocochlear Nerve ( Cranial Nerve 8):

    • Monitors balance, position, and movement

    • Monitors hearing

  • Accessory nerves ( Cranial Nerve 11):

    • Internal branches

      • Innervates voluntary swallowing muscles of the soft palate and pharynx (skeletal muscles)

    • External Branches

      • Controls muscles associated with the pectoral girdle

  • Hypoglossal Nerves (Cranial Nerve 12):

    • Provides voluntary motor control over tongue movement

• Parasympathetic Nervous System:

  • Responsible for actions of smooth muscles, cardiac muscles, and glands (stimulated the adrenal glands to stop/slow down)

• Sympathetic Nervous System:

  • It affects the same organs as the parasympathetic nervous system (does the same but brings the adrenal glands up

• Cranial Nerves and the Organs they affect:

• Nervous Tissue and Neuroglia:

  • Nervous Tissue: Found in the brain, spinal cord, and nerves. ( Function: reception of general sensory info, receiving and perceiving special sensations, integration of sensory information, and response generation)

  • Neuroglia: Homeostatic and defensive cells of the nervous system. The ultimate supportive cell of the nervous system, keeping it in a functional state.

• Sensory Cell

  • Cells that detect information such as light, touch, smell, taste, and temperature through receptors on their surface

• Function of the Nervous System:

  • Act as the body’s communication network, sending and receiving messages between different body parts and the external environment, controlling functions such as movement, sensation, thought, emotion, learning memory, etc.

• Dendrites:

  • Act as the body’s communication network, sending and receiving messages between different body parts and the external environment, controlling functions such as movement, sensation, thought, emotion, learning memory, etc.

• Receptor Cells:

  • A protein molecule to which substances like hormones, drugs, and antigens can bind