Chapter 2 Flashcards
Homeostasis
The internal environment in which your cell lives needs to be kept constant. Temperature, pH and concentrations of ions, glucose, water and carbon dioxide need to be within a particular range. Maintenance of this constant internal environment is called homeostasis.
Stimulus response-model
This is where a change occurs and this change is picked up by the receptors, after this has happened the body corrects this change and goes back to normal.
Negative feed back
This is when the body does the opposite of what is happening, for eg, if a certain chemical is not present in the blood stream then the body will start producing this chemical constantly.
Glucose
This is the simplest from of sugar is and is basically a from of food for the body.
Pancreas
A large gland in the body which secretes enzymes and helps the body to digest carbohydrates, fats and proteins.
Insulin
This is a chemical that removes glucose from the blood stream and stores it in the liver and muscles as glycogen.
Glycogen
This is the converted form of glucose and this is like the stored from of it, it can stored in muscle tissue or in the liver.
Positive feedback
Whereas negative feedback involves a response in an opposite direction to the stimulus, positive feedback 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. The response continues until the baby stops sucking and the stimulus is removed.
Oxytocin
As the baby moves into the cervix (the area that connects the uterus to the vagina), it causes stretching of receptors that result in the release of a hormone called oxytocin
Nervous system
A 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
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.
Multicellular organisms
An organism that is made up of many cells, most animals and plants are multicellular.
Central Nervous System
A part of the nervous system that is composed of the brain and spinal cord
Peripheral nervous system
The nerves that connect the central nervous system to the rest of the body.
Neurons
Nerve cell
Nerve
A bundle of Neurons
Sensory Neurons
Carry the impulse created by the stimulus to the central nervous system
Motor Neurons
These Neurons carry impulses from the central nervous system to effectors
Nucleus
An organelle of a cell, this is the control centre of a cell and also where all the DNA for other organelles are stored.
Interneuron
The Neurons that connect the sensory and motor Neurons together, the interneurons never touch the sensory or the motor Neurons but there is a small gap in between them called the synapse this is where the electrical message from the sensory Neurons travel to the interneurons through neurotransmitters then to motor Neurons.
Organelles
Small structures within a cell which help it survive.
Cytosol
This is a fluid found inside the cell.
Cell membrane
structure that encloses the contents of a cell and allows the movement of some materials in and out
Cell body
This contains nucleus and Neurons, 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 of the Neurons in the nervous system.
Synapse
The gap between the Neurons are called synapse.
Vesicles
A small cavity usually filled with fluid
Neurotransmitter
chemical released from the axon terminals into the synapse between your nerve cells (neurons) during a nerve impulse
