Bio 14 Week 2 Nervous System Pt. 1

Lec 2

Nervous system

1. A main homeostatic control system that links sensory input from the environment with behavioral responses.

2. It also changes in response to experience (memory)

Nervous system characteristics

Input → Interpretation center → Output

Learning/memory formation

________ and _______ can alter the output due to changes in the interpretation center

Afferent neuron

The afferent neuron carries sensory information from sensory receptors (such as mechanoreceptors or photoreceptors) toward the central nervous system (CNS). It responds to an incoming stimulus, such as heat, pressure, or light, and transmits this information to the integrating center.

Input to integration center

What is the pathway of information for an afferent neuron?

Peripheral

Afferent neurons are generally part of the ______ nervous system because they connect sensory receptors in the periphery (e.g., skin, muscles, and organs) to the CNS (e.g., the brain and spinal cord).

Integrating center

Part of the CNS that receives and processes sensory input from afferent neurons, interprets that information, and then generates an appropriate response.

Interneuron

Type of neuron that transmits signals between other neurons within the central nervous system (CNS), specifically connecting afferent (sensory) neurons to efferent (motor) neurons

Integrating center

Interneurons are primarily found in the __________ of the nervous system, which include the brain and spinal cord. These centers are part of the central nervous system (CNS)

Sensory Receptors

Specialized cells or nerve endings that detect specific types of stimuli from the environment or the body and send signals via afferent neuron

Efferent Neuron

Motor neurons that transmit signals away from the central nervous system (CNS) to effector organs (such as muscles or glands) to produce a response (Part of PNS)

Effector organs

Tissues/organs that respond to signals from efferent neurons, the output part of the nervous system response, carrying out actions necessary to respond to stimuli/maintain homeostasis.

Dendrite

the bushy, branching extensions of a neuron that receive messages/conduct impulses toward the cell body

cell body (soma)

Main part of neuron that's responsible for integrating signals from dendrites and initiating the action potential that travels down the axon.

Axon

Long, slender projection of a nerve cell that conducts electrical impulses (action potentials) away from the cell body toward other neurons, muscles, or glands, responsible for signal conduction.

Myelin sheaths

The material that covers axons

Axon terminal

Very end of a neuron's axon, which forms synapses with other neurons, muscle cells, or glands. Responsible for transmitting signals across the synapse

Synapse

a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter

Invertebrates

Animal that does not possess a backbone or vertebral column, includes majority of animal species such as insects, worms, jellyfish, snails, and starfish.

Larger/easier

Invertebrates often have _____ neurons which are ______ for physiological examination (ex: squid, marine snails, leeches)

simpler circuits

Invertebrates often have ________ which helps understand the basics of neuron behavior

Evolutionary origins

Comparisons of nervous systems across animals can inform us about the _________ of our own nervous system

Artificial neural networks

Knowledge gained from animal nervous systems has contributed to the development of _______

Radial symmetry

Symmetry about a central axis

Bilateral Symmetry

Symmetry where organism can be divided by a single plane into two mirror-image halves

Cnidarians

Invertebrate animals characterized by radial symmetry, a sac-like body with a single opening (mouth/anus), and specialized stinging cells (nematocysts), they tend to be marine/predatory

Hydra, jellyfish, coral

Cnidarian that is a solitary, carnivorous jellyfish-like animal often found in freshwater environments and known for its regenerative abilities.

Radial

Cnidarians are examples of organisms with _____ symmetryNer

Nerve net

A diffuse, decentralized nervous system that consists of a network of interconnected neurons spread throughout the body, allowing for basic responses to stimuli but lacking a centralized brain or ganglia.

Cephalization

Nerve tissues localize at the anterior (front) end of the body to form command center for the nervous system, typically associated with bilateral symmetry and directed movement

Invertebrates/vertebrates

Both ______ and _____ can have bilateral symmetry

Nerve cord

A major bundle of nerves that extends longitudinally through the body of many animals, serving to transmit signals between the brain (if present) and the rest of the body. In invertebrates, it is typically ventral, while in vertebrates, it is a dorsal, hollow structure (the spinal cord)

Ganglia

Clusters of nerve cell bodies that act as local processing centers

ganglia/nerve cord

In invertebrates with bilateral symmetry, the nervous system can present in _______ or _______

insects, flatworms, squid, leech

Examples of invertebrates with bilateral symmetry

fish, amphibians, reptiles, mammals

Examples of vertebrates with bilateral symmetry

brain/spinal cord/peripheral nerves

In vertebrates with bilateral symmetry, the nervous system usually presents as ______, ______, and _______

midbrain/smaller

In mammal brains, the _____ is _____ compared to other vertebrates

forebrain/cerebellum/larger

In mammal brains, the _____ and ________ is _____ compared to other vertebrates

Quadruped

an animal with four feet

Biped

an animal with two feet