Flashcards in Chapter 11: Human nervous system Deck (50):
What are some examples of things your body must maintain via homeostasis?
Body temperature, blood water, blood ions, blood glucose concentration
What is homeostasis?
The involuntary regulation of a internal environment of an organism to maintain optimal conditions
How does the CNS coordinate your actions?
The brain detects input from the receptors and coordinates a response, motor neurons carry the signal from the brain to the effectors
What are hormones?
Proteins which are released into the bloodstream by certain glands. When they reach their target organ, they can make a change. They are much slower than electrical impulses
What are nerves made of?
Long bundles of individual neurons
What are effectors?
Parts of the body that cause a response to stimuli by moving parts of the body or secreting hormones
What are receptors?
Cells at the beginning of a neuron pathway that detect changes in the environment and generate electrical responses. Fingertips contain the most receptors
Name some examples of receptors
Eyes (react to light), hearing (react to sound and position), taste (react to chemicals in food), smell (react to chemicals in air), touch (react to pain, itch, temperature, touch, pressure)
What are sensory neurons?
A neuron that carries an impulse from a receptor to the brain
What are relay neurons?
The neurons that pass signals along within the brain
What are motor neurons?
The neurons that carry signals from the CNS to muscles and glands
What is the stimulus/response pathway?
Stimulus, Receptor, Neurons, Effector, Response
What is a synapse?
A small gap between the axon of one neuron and the dendrites of another where chemical neurotransmitters can be exchanged
What are dendrites?
The branched beginning of neurons, which can detect neurotransmitters and start an electrical response
What happens at the end of axons?
The signal spreads out into root-like structures at the end of the cell, where it is temporarily converted into a chemical signal, which diffuses across the synapse
What are reflex responses?
Fast, involuntary responses that do not require the brain (e.g. moving your hand away from a hot surface)
What is a reflex arc?
The route if an impulse that bypasses the brain. Sensory neurons -> relay neurons in spine -> motor neurons. You know this response has happened because separate neurons carry an impulse from the relay neurons to the brain
What is the cerebral cortex?
The main, outer part of the brain, which is responsible for memories, consciousness, intelligence and language, and is split up into left and right hemispheres
What is the cerebellum?
A part of the brain near the spinal cord that coordinates muscle movement
What are the 4 lobes of the cerebral cortex?
Frontal (voluntary movements), Parietal (sensory information), Occipital (visual information), Temporal (memories/language)
What is the medulla oblongata?
A part of the brain above the spinal cord that controls breathing and heart rate
Where did neuroscience originate?
Ancient Egypt, yet many cultures around the world practiced trepanning
How did neuroscience develop?
Hippocrates was probably the first person to believe that senses and intelligence were related to the brain. Paul Broca found that patients with speech impediments had lesions in areas of the frontal lobe.
What is the state of neuroscience today?
Computers and MRI scanning are used for research. People with brain damage have had parts of their brains electronically stimulated, before being looked at using MRI
What determines an animal or human's behaviour?
Small changes in how effective synapses are
How do humans store memories?
Small groups of neurons constantly firing impulses at each other. Long-term memories are stored in the hippocampus
What is the cornea?
The transparent part that covers the pupil and refracts light into it
What is the lens?
The structure behind your pupil that further refracts light into the retina. Its shape is changed during accommodation
What is the iris?
The coloured muscle around your pupil that controls how much light enters the eye
What is the ciliary body?
A structure made of ciliary muscles, which contract and relax to change the shape of the lens
What is the retina?
The layer of rods and cones at the back of the eye
What is the fovea?
An area of sharp vision on the retina where light can fall directly on cones
What is the optic nerve?
The nerve that transmits sight information from the eye to the brain
What is the sclera?
The white, outer area that protects the rest of the eye
What is the choroid?
The layer of the eye between the sclera and the retina that provides oxygen and nourishment to the cells of the retina
What are rods?
Light-sensitive receptor cells on the retina that allow you to see in low-light conditions
What are cones?
Light-sensitive receptor cells on the retina that allow you to see in colour
What happens when we focus on near/far objects?
The ciliary muscles contract/relax and the lens becomes shorter/longer
What is myopia and what causes it?
A medical condition where people can not see far-away objects, caused by the eyeball being too long
What is hyperopia and what causes it?
A medical condition where people can not see near objects, caused by the eyeball being too short, the cornea not curved enough, or the lens not being thick enough
What part of your brain regulates your temperature?
Your thermoregulatory center keeps your body at ~37C, the optimum temperature for enzymes
How does it regulate your temperature?
It measures the temperature of the blood flowing through the brain, as well as using the receptors on the skin. It then employs one of its many techniques to control body temperature
How does sweating work?
Sweat glands in your skin start to produce sweat, which evaporates, transferring away heat energy
How does shivering work?
Skeletal muscles rapidly contract and relax to generate heat
What is vasodilation?
When the arteriole muscles relax to direct more blood to the surface of the skin, increasing heat loss
What is vasoconstriction?
When the arteriole muscles contract to direct blood away from the surface of the skin, decreasing heat loss
How is the endocrine system different from the nervous system?
Hormones are secreted by glands and slowly transmitted by blood in reaction (sometimes in reaction to internal stimuli) and have a long lasting response. They also only target receptor cells
How are hyperopia and myopia treated?
Wearing glasses or contacts which refract the light before it enters your eyes
What is the brainstem?
The area of the brain that connects the brain to the spine