Nervous Tissue Lecture 1 Flashcards
Neurology
Definition: The study of the nervous system.
Example: Researching brain functions falls under the realm of neurology.
Neurologist
A medical professional specializing in diagnosing and treating disorders of the nervous system.
Main Roles of the Nervous System
- Sense, interpret, and respond to
stimuli - Initiates movement and gland
secretion - Produces thoughts, emotions, and
memories
Sensory Function
Definition: Involves detecting external or internal stimuli and transmitting signals towards the central nervous system.
Utilizes afferent (sensory) neurons
Integrative Function
Definition: Processing incoming signals from afferent neurons and determining the appropriate response.
Utilizes interneurons
Motor Function
Definition: Involves transmitting commands from the central nervous system to effectors like muscles and glands.
Utilizes efferent (motor) neurons
Afferent Neurons
Definition: Neurons that carry signals towards the central nervous system.
Interneurons
Neurons located within the brain and spinal cord that facilitate communication between sensory and motor neurons.
Efferent Neurons
Neurons that carry signals away from the central nervous system to effectors like muscles and glands.
Central Nervous System (CNS)
The division of the nervous system comprising the brain and spinal cord.
Importance of the Brain
- The brain is situated within the cranial cavity, protected by the skull.
- The brain is one of the most vital organs for survival
Layers of Brain Protection
Three layers of protection: cranial bones, meninges, and cerebrospinal fluid.
Cerebrospinal Fluid (CSF)
Fluid similar in composition to blood plasma, providing buoyancy and protection for the brain and spinal cord.
Division of the Cerebrum
The cerebrum, the largest part of the brain, is divided into two hemispheres: left and right.
The RIGHT side receives
information from and controls the LEFT side of
the body (and vice versa)
* Not always true
Correlation of Brain Size with Intelligence
Brain size alone is not necessarily correlated with intelligence or complexity.
Anatomy of the Spinal Cord
Part of the central nervous system that extends from the brain to the lower back.
Starting and Ending Points
Begins at the foramen magnum (opening at the base of the skull) and ends at the level of the L1/L2 vertebrae.
Location within the Vertebral Column
Located within the vertebral canal, a hollow space formed by the vertebral column
Internal Structure of the Spinal Cord
Consists of internal gray matter and external white matter.
Ascending Tracts
Bundles of nerve fibers in the spinal cord that carry sensory information towards the brain
Descending Tracts
Nerve pathways that carry motor commands from the brain to the spinal cord and peripheral nerves
Peripheral Nervous System (PNS)
Consists of all nervous tissue outside the central nervous system (CNS), including nerves and sensory receptors.
Spinal Nerves
Nerves that exit directly from the spinal cord and carry both sensory and motor information.
Cranial Nerves
Nerves that exit directly from the brain or brainstem and carry sensory and motor information.
Sensory and Motor Neurons
- Sensory neurons transmit sensory inputs towards the CNS
- Motor neurons carry information away from the CNS to effector organs.
Somatic Nervous System
Part of the PNS responsible for voluntary motor control of skeletal muscles and processing sensory information.
Autonomic Nervous System (ANS)
Controls involuntary functions of smooth muscle, cardiac muscle, and glands, regulating activities like heart rate, digestion, and breathing.
Sympathetic Nervous System (SNS)
Division of the ANS responsible for the “fight or flight” response, activating physiological changes to prepare the body for action.
Parasympathetic Nervous System (PSNS)
Division of the ANS that promotes “rest and digest” activities, conserving energy and restoring the body to a calm state after stress.
Enteric Nervous System (ENS)
A division of the PNS that controls gastrointestinal function independently of the CNS, regulating processes like digestion and gut motility.
Neurons
Specialized cells of the nervous system responsible for transmitting nerve impulses.
Neuroglia
Supportive cells of the nervous system that provide structural support and insulation for neurons.
Anatomy of a Neuron
Cell body (perikaryon)
Dendrites: Receive input from other neurons or sensory receptors.
Axons: Conduct action potentials away from the cell body.
Axon hillock: Area where the axon joins the cell body.
Axon terminals: Endings of axons where neurotransmitters are released.
Nissl Bodies
Large granular bodies found within the neuronal cell body consisting of rough endoplasmic reticulum.
Synapse
Connection between two neurons or between a neuron and an effector.
Unipolar (Pseudounipolar) Neurons
Dendrites and one axon are fused together to form a continuous process emerging from the nerve cell body
Bipolar Neurons
Characterized by having one axon and one main dendrite.
Multipolar Neurons
Typically possess multiple dendrites and one axon.
Purkinje Neurons
Neurons with massive, intricately branched, flat dendritic trees found only in the cerebellum.
Pyramidal Neurons
Neurons with a pyramidal cell body found only in the cerebral cortex.
