Biology Flashcards
Sequence of Stimulating the Next Neuron
Neurotransmitter –> Synapse –> Dendrite
What is a neuron?
The basic cell that makes up the nervous system and is responsible for receiving and sending messages within that system.
What is the function of the myelin sheath?
It acts like insulation for the neuron, helping to speed up the transmission of electrical signals along the axon.
What are the three main parts of a neuron?
Dendrites, axon, and cell body (soma).
What is the function of dendrites?
To receive messages from other neurons and send them toward the cell body.
What is the function of the axon?
To carry electrical impulses away from the cell body toward other neurons, muscles, or glands.
What is the synapse?
The gap between two neurons where neurotransmitters are released to transmit messages.
What are axon terminals?
Rounded areas at the ends of branches at the end of the axon, responsible for communicating with other nerve cells by releasing neurotransmitters.
What are synaptic vesicles and their function inside the axon terminal?
Synaptic vesicles are sack-like structures inside the axon terminal that contain neurotransmitters. When released, these neurotransmitters have an effect on the next cell, facilitating communication between neurons.
What is the all-or-none principle in neural impulses?
The all-or-none principle states that a neuron either fires completely or does not fire at all. After firing, the neuron returns to its resting potential.
What is the role of the synapse in neuron communication?
The synapse (gap), is a fluid-filled space between the axon terminals of the pre-synaptic neuron and the dendrites or surface of the post-synaptic neuron, where neurotransmitters are released to communicate between cells.
What are receptor sites on the post-synaptic neuron?
Receptor sites are holes in the surface of the dendrites, shaped to fit specific neurotransmitters, functioning like a “lock and key” mechanism.
How do neurons communicate through neurotransmitters?
Neurons communicate by using excitatory and inhibitory neurotransmitters:
Excitatory neurotransmitters
activate the receiving cell, causing it to fire.
Inhibitory neurotransmitters
deactivate the receiving cell, causing it to stop firing.
What are agonists in the context of neurotransmitter effects?
Chemical substances (e.g., drugs) that mimic or enhance the effects of a neurotransmitter on receptor sites, increasing or decreasing receptor activity.
What are antagonists in the context of neurotransmitter effects?
Chemical substances that block or reduce the action of neurotransmitters, inhibiting the cell’s response.
Acetylcholine (ACh)
Excitatory/Inhibitory; arousal, attention, memory, controlling muscle contractions
Norepinephrine (NE)
Mainly excitatory; arousal + mood
Dopamine (DA)
Excitatory/Inhibitory; sleep, mood, anxiety, appetite; control of movement and sensing pleasure
Serotonin (5-HT)
Excitatory/Inhibitory; sleep, mood, anxiety, appetite
Gaba-aminobutric Acid (GABA)
MAJOR INHIBITORY NEUROTRANSMITTER; sleep and movement
Glutamate
MAJOR excitatory neurotransmitter; learning, memory formation, nervous system development, and synaptic plasticity
Endorphins
Inhibitory neural regulators; pain relief
What is the process of reuptake?
The process by which neurotransmitters are taken back into synaptic vesicles after being released into the synapse.
What is the process of enzyme activity in muscle control?
For rapid muscle control, the enzyme acetylcholinesterase breaks down acetylcholine, a neurotransmitter, as reuptake would be too slow for muscle activity.
What is reuptake in neuronal communication?
Reuptake is the process where neurotransmitters are taken back into synaptic vesicles after being released into the synapse.
How does enzyme activity assist in muscle control?
The enzyme acetylcholinesterase breaks down acetylcholine, a neurotransmitter important for muscle control, because muscle activity needs to happen quickly and reuptake would be too slow.
What are the main components of the Central Nervous System (CNS)?
brain and spinal cord
What is the function of the spinal cord in the CNS?
The spinal cord carries messages to and from the body and brain and is responsible for very fast, lifesaving reflexes.
What does a sensory neuron do?
Carries info from the senses to the CNS. (afferent neuron.)
What is neuroplasticity?
The brain’s ability to change its structure and function in response to experience or trauma.
“Neurons that fire together wire together.”
What is the function of a motor neuron?
Carries commands from the CNS to the muscles. (efferent neuron)
What role does an interneuron play in the reflex arc?
An interneuron is found in the center of the spinal cord (CNS), receives information from sensory neurons, and sends commands to the muscles through motor neurons. Interneurons also make up the majority of neurons in the brain.
What is the peripheral nervous system (PNS)?
The peripheral nervous system consists of all nerves and neurons that are not part of the brain and spinal cord but run through the body.
How is the PNS divided?
-Somatic Nervous System (voluntary)
-Autonomic Nervous System (involuntary)
What is the somatic nervous system?
The somatic nervous system is a division of the peripheral nervous system (PNS) that carries information to and from the (CNS)
What are the pathways of the Somatic Nervous System?
Sensory pathway: Nerves carry information from sensory organs to the CNS, consisting of sensory neurons.
Motor pathway: Nerves carry commands from the CNS to voluntary muscles, consisting of motor neurons.
What is the autonomic nervous system (ANS)?
The autonomic nervous system (ANS) is a division of the peripheral nervous system (PNS) responsible for controlling involuntary muscles, organs, and glands.
What are the pathways of the Autonomic Nervous System ?
Sympathetic division (fight-or-flight): Reacts to stressful events and causes bodily arousal.
Parasympathetic division (rest and repair): Restores the body to normal after arousal and manages day-to-day functions of organs and glands.
What does the endocrine gland (EG) do?
The endocrine glands secrete hormones directly into the bloodstream.
Pituitary gland (EG)
Located in the brain, secretes human growth hormone, and influences all other hormone-secreting glands (the master gland).
Gonads (ovaries and testes) (EG)
Regulate sexual development, behavior, and reproduction.
Pineal gland (EG)
Located near the base of the cerebrum, secretes melatonin.
Pancreas (EG)
Controls blood sugar levels.
Thyroid gland (EG)
Found in the neck, regulates metabolism.
Adrenal glands (EG)
Located on top of each kidney, Produce hormones to deal with stress, regulate salt, and provide sex hormones.
Limbic System
A group of brain structures located under the cortex, involved in learning, emotion, memory, and motivation.
Includes:
-Thalamus
-Hypothalamus (regulates temperature, hunger, thirst, and circadian rhythms)
-Amygdala (involved emotions, particularly fear and pleasure)
-Cingulate Cortex (plays a role in emotional regulation and processing)
-Hippocampus (essential for forming new memories and learning)
Thalamus
Located in the center of the brain.
-Relays sensory information from the lower brain to the appropriate areas of the cortex.
-Processes some sensory information before sending it to its proper area.
Occipital Lobe
Located at the rear and bottom of each cerebral hemisphere.
Contains the visual centers of the brain.
-Primary Visual Cortex: Processes visual information from the eyes.
-Visual Association Cortex: Identifies and makes sense of visual information.
Parietal Lobe
Located at the top and back of each cerebral hemisphere.
Contains centers for touch, taste, and temperature sensations.
Somatosensory Cortex
Area of neurons running down the front of the parietal lobes, responsible for processing information from skin and internal body receptors for:
-Touch
-Temperature
-Body position (proprioception)
-Possibly taste
Temporal Lobe
Areas of the cortex located just behind the temples.
Contains neurons responsible for the sense of hearing and meaningful speech.
-Primary Auditory Cortex: Processes auditory information from the ears.
-Auditory Association Cortex: Identifies and makes sense of auditory information.
Frontal Lobe
Located in the front and top of the brain.
Responsible for:
- Higher mental processes and decision making (executive function).
- Production of fluent speech.
Motor Cortex
Section at the back of the frontal lobe responsible for sending motor commands to the muscles of the somatic nervous system.
Association Areas of Cortex
Areas within each lobe of the cortex responsible for the coordination and interpretation of information.
Higher Mental Processing
Involves complex cognitive functions such as reasoning, problem-solving, and planning that occur in the association areas of the cortex.
Broca’s Aphasia
Cause: Damage to Broca’s area (left frontal lobe)
Symptoms:
-Speech problems
-Difficulty speaking fluently
-Mispronunciation
-Halting speech
Wernicke’s Aphasia
Cause: Damage to Wernicke’s area (left temporal lobe)
Symptoms:
-Inability to understand language
-Difficulty producing meaningful speech
Spatial Neglect
Cause: Damage to right hemisphere association areas
Symptoms:
-Inability to recognize objects/body parts in left visual field
Left Hemisphere Functions
Controls:
-Language
-Writing
-Logical thought
-Analysis
-Mathematical abilities
Processing: Information sequentially
Influences: Enables speech
Cerebrum
Upper part of the brain consisting of two hemispheres and their connecting structures
Split-Brain Research
Definition: Study of patients with severed corpus callosum
Focus: Sending messages to only one side of the brain
Purpose: Demonstrates right and left brain specialization
Right Hemisphere Functions
Controls:
-Emotional expression
-Spatial perception
-Recognition of faces, patterns, melodies, and emotions
Processing: Information globally
Influences: Does not influence speech
