Nervous System and Sensory Reception Flashcards
The NS regulates body structures and processes to maintain homeostasis.
Define homeostasis.
Stability within the body.
Two types of cells are found in the NS. Identify their names and functions.
- Neurons: Specialized cells that can receive and send electrochemical signals called impulses and respond to stimuli.
- Glial cells: “Nanny cells” that support, nourish, and protect neurons.
List the structures that make up the CNS and its role in the body.
- Brain
- Spinal cord
The role of the CNS is to receive information from the senses, integrate it, and then generate a response.
What is the function of dendrites?
They receive impulses from other neurons and relay them down the cell.
What is the function of the cell body?
It processes input from dendrites and relays it to the axon.
What is the function of an axon?
Area in the neuron where the nerve impulse takes place (where electricity is generated and transmitted).
What is the function of the myelin sheath?
It protects myelinated neurons and speeds the rate of nerve impulse transmission.
What are the Nodes of Ranvier?
Spaces between Schwann cells where the impulse (electricity) can travel.
What is the function of sensory neurons?
Receive stimuli and send info to CNS for interpretation.
What is the function of motor neurons?
Carry responses from the CNS to the PNS.
What is the function of interneurons?
Sends info within the CNS.
What is resting membrane potential?
The potential difference across the membrane in a resting neuron.
What does resting potential do?
It provides energy for the generation of a nerve impulse in response to an appropriate stimulus.
What is the sodium-potassium exchange pump?
System involving carrier proteins in the plasma membrane - that uses the energy of ATP to:
Transport 3 sodium ions out and 2 potassium ions in.
What is saltatory conduction?
The conduction of an impulse along a myelinated neuron.
What is the synaptic terminal?
The end of the axon that converts electrical energy (action potentials) into chemical energy (neurotransmitters)
What are synaptic vesicles?
Sacs that contain NTs and release them into the synaptic cleft (through exocytosis).
What are the excitatory effects that the neurotransmitters have on the postsynaptic membrane?
Receptor proteins allow ion channels to open
Sodium ions rush into the postsynaptic membrane
Membrane becomes depolarized (cannot experience action potential)
Slight depolarization spreads throughout the nerve (reducing threshold level)
What are the inhibitory effects that neurotransmitters have on post synaptic membrane?
Receptors trigger potassium ion channels to open
Potassium ions flow out, hyperpolarization occurs (more negative transmembrane potential)
What is Acetylcholine?
NT used to control most neurons and effectors.
What is Cholinesterase?
Enzyme that removes Ach from the synapse when the job is done to prevent overstimulation.
What is dopamine?
NT that controls body movements.
Lack of = Parkinson’s tremors
What is serotonin?
NT that controls mood, attention, sleep, appetite.
Lack of = depression, OCD, other mood disorders
What are endorphins?
Nature’s painkillers, released during extreme stress to prevent pain signals.
Low = risk of alcoholism and other pleasure-seeking behaviours
What is epinephrine?
Fight or flight, increases heart rate, respiration, sugar to muscles.
Low = less adaptable to stress
What is the medulla oblongata’s function?
Controls your autonomic NS (involuntary), fight or flight (heart rate, respiration, digestion).
What is the cerebellum’s function?
Muscle coordination, fine motor skills, and balance.
What is the pons’ function?
“Bridge” - communication link between the cerebrum and cerebellum.
Walking, talking, reading … requires communication btwn them.
What is the hypothalamus’ function?
“Complaint box” - constantly receiving info from the body, maintains body temp
The cerebrum is divided into ___ hemispheres and communicates via the ___
2 (right and left)
corpus callosum
Occipital lobe
Vision and interpretation of visual stimuli
Temporal lobe
Hearing and interpretation of auditory stimuli
Parietal lobe
Sensory info from the skin (pressure, temperature, pain)
Frontal lobe
Planning, memory, personality, decision-making, risk-taking, and gross-motor cortex and speech center
What is the function of the sensory somatic NS?
Focuses on the external environment and controls voluntary (somatic) and involuntary (autonomic) skeletal muscle movements.
What is the function of the autonomic NS?
Focuses on the internal environment and controls “autonomic” functions of the body’s internal systems:
Sympathetic: “Fight, flight, or freeze”, prepares the body for stress
Parasympathetic: “Rest and digest”, returns the body to resting conditions after a stress
What are sensory receptors?
Specialized dendrites, modified to receive a particular type of stimulus.
What is the pupillary reflex?
Iris relaxes/contracts to change size of the pupil (more/less light in).
What are accomadation reflexes?
Lens changes shape to focus on objects near and far.
