Control and Coordination Flashcards
Multicellular Organism
Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms.
Homeostasis
Maintenance of a relatively stable internal environment. Keep internal factor in the optimal range
Stimulus-Response model
The stimulus-response model is a characterization of a statistical unit
Negative Feedback
the diminution or counteraction of an effect by its own influence on the process giving rise to it, as when a high level of a particular hormone in the blood may inhibit further secretion of that hormone, or where the result of a certain action may inhibit further performance of that action.
Glucose
a simple sugar which is an important energy source in living organisms and is a component of many carbohydrates.
Pancreas
a large gland behind the stomach which secretes digestive enzymes into the duodenum. Embedded in the pancreas are the islets of Langerhans, which secrete into the blood the hormones insulin and glucagon.
Insulin
a hormone produced in the pancreas by the islets of Langerhans, which regulates the amount of glucose in the blood. The lack of insulin causes a form of diabetes.
Glycogen
a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide which forms glucose on hydrolysis.
Positive feedback
In a positive feedback system, the output enhances the original stimulus.
Oxytocin
a hormone released by the pituitary gland that causes increased contraction of the uterus during labour and stimulates the ejection of milk into the ducts of the breasts.
Nervous system
the system of nerves and nerve centres in an animal in which messages are sent as an electrical and then a chemical impulse. It comprises the central nervous system and the peripheral nervous system.
Endocrine system
the body system of glands that produce and secrete hormones into the bloodstream in order to regulate processes in various organs
Signalling molecules
a chemical involved in transmitting information between cells
Central Nervous System
the part of the nervous system composed of the brain and spinal cord
Peripheral Nervous System
made up of sensory and motor neurons. It connects the central nervous system to the rest of the body and detects and responds to change.
Sensory Neurons
a nerve cell in the sense organs. It detects change in the environment and sends a message to the central nervous system.
Motor Neurons
the nerve cell that causes an organ, such as a muscle or gland, to respond to a stimulus
Endocrine Glands
organs that produce hormones. Endocrine glands release their hormones into the bloodstream for transport to target organs.
Hormones
chemical substances produced by glands and circulated in the blood. Hormones have specific effects in the body.
Thermoregulation
the control of body temperature
Thermostat
a device that establishes and maintains a desired temperature automatically
Neurons
nerve cell
Nerves
a bundle of neurons
Interneurons
a nerve cell that carries nervous impulses through the central nervous system. They provide the link between sensory neurons and motor neurons.
Motor Neurons
the nerve cell that causes an organ, such as a muscle or gland, to respond to a stimulus
Nucleus
central part of an atom, made up of protons and neutrons; roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.
Organelles
small structure in a cell with a special function
Cytosol
the fluid found inside cells
Cell Membrane
structure that encloses the contents of a cell and allows the movement of some materials in and out
Cell Body
contains the nucleus of a neuron, also called grey matter
Dendrites
structure that relays information towards the cell body of a neuron
Axon
an appendage of the neuron that nervous impulses travel along to the next neuron or to an effector organ (muscle or gland)
Myelin
a fatty, white substance that encases the axons (connecting branches) of the neurons in the nervous system
Synapse
the gap between adjoining neurons across which electrical nervous impulses are sent
Neurotransmitters
chemical released from the axon terminals into the synapse between your nerve cells (neurons) during a nerve impulse
Effector
an organ that responds to a stimulus
Reflex arc
a nervous pathway involving a small number of neurons. A reflex occurs when nervous impulses travel from the receptor to the spinal cord and then to the effector organ.
Thinking
active consideration involving the brain neurons
Conscious Response
actions taken after the brain receives information from one of the sense organs
Vesicles
a small cavity, usually filled with fluid
Sense Organs
a specialised structure that detects stimuli (such as light, sound, touch, taste and smell) in your environment
Stimuli
changes in the environment that can be detected and responded to
Thermoreceptors
special cells located in your skin, part of your brain and body core that are sensitive to temperature
Mechanoreceptors
special cells within the skin, inner ear and skeletal muscles that are sensitive to touch, pressure and motion, enabling you to balance, hear and sense pressure and movement
Chemoreceptors
special cells within a sense organ (especially the nose and tastebuds) that are sensitive to particular chemicals, giving you the sensations of smell and taste
Photorecptors
a receptor cell located in your eye that is stimulated by light, converting it to electrical energy that is sent to the brain, giving you the sensation of light
Pain Receptors
special cells located throughout the body (except the brain) that send nerve signals to the brain and spinal cord in the presence of damaged or potentially damaged cells, resulting in the sensation of pain
Hot Thermoreceptors
a type of receptor in your skin that can detect an increase in skin temperature above 37.5°C (normal body temperature)
Cold Thermoreceptors
a type of receptor in your skin that can detect a decrease in skin temperature below 35.8 °C
Olfactory nerve
nerve that sends signals to the brain from the chemoreceptors in the nose
Pupil
a hole through which light enters the eye
Iris
coloured part of the eye that opens and closes the pupil to control the amount of light that enters the eye
Reflex Action
a quick response to a stimulus. Reflex actions do not involve thought.
Cornea
the curved, clear outer covering of your eye
Lens
a transparent curved object that bends light towards or away from a point called the focus. The eye has a jelly-like lens.
Retina
curved surface at the back of the eye. It is lined with sight receptors.
Short-sightedness
the condition of not being able to see clearly things that are far away
Long-sightedness
the condition of not being able to see clearly things that are close
Optic nerve
large nerve that sends signals to the brain from the sight receptors in the retina
Rods
sensory receptors in the retina that respond to low levels of light and allow you to see in black and white in dim light
Cones
sensory receptors in the retina that respond to red, green or blue light. Cones are mainly in the central part of the retina.
Colour blindness
an inherited condition, more common in males, in which a deficiency of one or more of the different types of cones may mean that you find it difficult to see a particular colour or combinations of colours
Ear canal
the tube that leads from the outside of the ear to the eardrum
Eardrum
a thin piece of stretched skin inside the ear that vibrates when sound waves reach it
Ossicles
a set of three tiny bones that send vibrations from the eardrum to the inner ear. They also make the vibrations larger.
Middle Ear
the section of the ear between your eardrum and the inner ear, containing the ossicles
Cochlea
the snail-shaped part of the inner ear. It is lined with tiny hairs that are vibrated by sound and stimulate the hearing receptors.
Auditory nerve
a large nerve that sends signals to the brain from the hearing receptors in the cochlea
Tongue
the sense organ responsible for taste
Tastebuds
nerve endings located in your tongue that contain receptors sensitive to sweet, salty, bitter, sour and savoury chemicals, allowing you to experience taste
Papilla
bumps on your tongue that are thought to contain tastebuds
