Chapter 11: Human nervous system Flashcards Preview

GCSE Biology > Chapter 11: Human nervous system > Flashcards

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


What is the difference between a monosynaptic and a polysynaptic reflex arc?

Monosynaptic reflexes only have 1 synapse (Sensory -> Motor) and do not involve the brain