Chapter 2- Control and Cooridination Flashcards
Multicellular Organism
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 Feedback
a response that reduces the original stimulus
Glucose
a simple carbohydrate and the simplest form of sugar
Pancreas
large gland in the body that produces and secretes the hormone insulin and an important digestive fluid containing enzymes
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
Positive Feedback
a reaction in which the response is in the same direction as the stimulus—for example, during childbirth the onset of contractions activates the release of the hormone oxytocin, which stimulates further contractions
Oxytocin
hormone secreted from the pituitary gland that assists in the formation of bonds between mothers and their babies, and perhaps between people in close relationships
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
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
Thermostat
device that establishes and maintains a desired temperature automatically
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
Thermorereceptors
special cells located in your skin, part of your brain and body core that are sensitive to temperature
Mechanoreptors
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
Photoreceptors
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
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
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-Sidedness
the condition of not being able to see clearly things that are far away
Long-Sidedness
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
Dendrites
structure that relays information towards the cell body of a neuron
Cognition
another name for thinking or mental activity
Emotions
feelings, such as happiness, sadness and anger, that are interpreted by the brain
Regulating
the process by which the brain detects and responds to the body’s internal and external environments
Hindbrain
a continuation of the spinal cord
Pons
part of the brain involved in regulating sleep, arousal and breathing, and coordinating some muscle movements
Medulla oblongata
a part of the brain developed from the posterior portion of the hindbrain and continuing with the spinal cord; see also brain stem
Reticular formation
a network of neurons that opens and closes to increase or decrease the amount of information that flows into and out of the brain
Forebrain
consists of the cerebrum, cerebral cortex, thalamus and hypothalamus
Cerebral cortex
the outer, deeply folded surface of the cerebrum
Thalamus
part of the brain through which all sensory information from the outside (except smell) passes before going to other parts of the brain for further processing
Hypothalamus
monitors internal systems and controls the release of hormones to maintain the normal body state (homeostasis)
Hippocampus
part of the brain with a key role in consolidating learning, comparing new information with previous experience, and converting information from working memory to long-term storage
Brain Stem
the part of the brain connected to the spinal cord, responsible for breathing, heartbeat and digestion. Sometimes called the medulla.
Cerebellum
the part of the brain that controls balance and muscle action
Cerebrum
the largest part of the brain (about 90 per cent of total brain volume), responsible for higher order thinking, controlling speech, conscious thought and voluntary actions. It is made up of the frontal, temporal, parietal and occipital lobes.
High order thinking
involves problem solving and decision making
Cerebral hemispheres
the left and right halves of the brain
Corpus callosum
a bridge of nerve fibres through which the two cerebral hemispheres communicate
Synaethesia
a condition in which a sensation is produced in one physical sense when a stimulus is applied to another; affected people may associate letters with a flavour, numbers with a gender or sounds with colour
Functional magnetic resonance imaging (fMRI)
a type of specialised MRI scan used to measure the change in blood flow related to neural activity in the brain or spinal cord
Analogies
a similarity between two or more things on which a comparison may be based
Hormones
chemical substances produced by glands and circulated in the blood. Hormones have specific effects in the body.
Endocrine glands
organs that produce hormones. Endocrine glands release their hormones into the bloodstream for transport to target organs.
Target cells
cells in the body that respond to a particular hormone
Pituitary glands
a small gland at the base of the brain that releases hormones
Hypothalamus
monitors internal systems and controls the release of hormones to maintain the normal body state (homeostasis)
Pineal Glands
gland that produces the hormone melatonin, which can make you feel drowsy
Thermoregulation
the control of body temperature
Pancreas
a large gland in the body that produces and secretes the hormone insulin and an important digestive fluid containing enzymes
Insulin
hormone that removes glucose from the blood and stores it as glycogen in the liver and muscles
Glucose
a simple carbohydrate and the simplest form of sugar
Glycogen
the main storage carbohydrate in animals, converted from glucose by the liver and stored in the liver and muscle tissue
Glucagon
a hormone, produced by the pancreas, that increases blood glucose levels
Corpus luteum
an endocrine structure that is involved in the production of progesterone
Progesterone
progesterone is involved in the menstrual cycle but it is also involved in pregnancy
Fertilisation
penetration of the ovum by a sperm
Menstruation
for about 5 days each month, women menstruate (have their period)
Menstrual Cycle
cyclic changes in the ovaries and lining of the uterus as a result of changing hormone levels in the blood
