Chapter 2: Control And Coordination Flashcards
Multicellular
an organism that is composed of many cells. Most plants and animals are multicellular.
Homeostasis
the maintenance of a relatively constant internal physiological environment of the body or part of the body (e.g. blood glucose level, pH, body temperature) in varying external conditions
Stimulus response model
a system in which any changes or variations (stimuli) in the internal environment are detected (by receptors); if a response is required, this is communicated to effectors to bring about some type of change or correction so the conditions can be brought back to normal
Negative feed back system
occurs when the response is in an opposite direction to the stimulus. For example, if levels of a particular chemical in the blood were too high, then the response would be to lower them. Likewise, if the levels were too low, then they would be increased.
Glucose
A simple carbohydrate and the simplest form of sugar
Pancreas
a large gland in the body that produces and secretes the hormone insulin and an important digestive fluid containing enzymes
Positive feedback system
results in the response going in the same direction. An example of positive feedback is when a mother is breastfeeding her baby. Mechanoreceptors in her nipple detect the baby sucking. The message is transferred to her central nervous system (in this case, her spinal cord) which then sends a message to muscles lining the milk glands to respond by releasing milk
Insulin
hormone that removes glucose from the blood and stores it as glycogen in the liver and muscles
Glycogen
the main storage carbohydrate in animals, converted from glucose by the liver and stored in the liver and muscle tissue
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.
CNS (central nervous system)
the part of the nervous system composed of the brain and spinal cord
PNS (periphial 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.
Endocrine system:
the body system of glands that produce and secrete hormones into the bloodstream in order to regulate processes in various organs
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
Neurotransmitters
chemical released from the axon terminals into the synapse between your nerve cells (neurons) during a nerve impulse
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
Neurons
Nerve cell
Interneurons
nerve cell that carries nervous impulses through the central nervous system. They provide the link between sensory neurons and motor neurons.
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
Vesicles
a small cavity, usually filled with fluid
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.
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
Thermo receptors
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
Photo receptor
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
Hypothalamus
monitors internal systems and controls the release of hormones to maintain the normal body state (homeostasis)
Brain Stem
the part of the brain connected to the spinal cord, responsible for breathing, heartbeat and digestion. Sometimes called the medulla.
Target cells
cells in the body that respond to a particular hormone
Pituitary gland
A pea size gland that sits at the bridge of your nose. Your thyroid gland, ovaries and testes are all controlled by hormones released by this endocrine gland. Hormones released by the pituitary gland can control water balance, growth, development and reproduction-related processes.
Pineal Gland
gland that produces the hormone melatonin, which can make you feel drowsy
