B5 : Seneca ACTIVE Flashcards
What is Homeostasis
Homeostasis describes all of the processes that happen in a cell or organism to maintain (keep) optimal conditions
This is needed to respond to changes in the internal and external environment.
Enzyme Functioning
Because humans are organisms that live in a changing environment, we must regulate our body’s internal conditions to make sure our enzymes and cells function well.
Denaturing
If conditions are not optimal, then our enzymes can denature (change shape).
This reduces their ability to catalyze (speed-up) metabolic reactions (chemical reactions in organisms).
Why do humans need to regulate the internal conditions of the body
Humans must regulate their body’s internal conditions to make sure that enzymes and cells function well
What are the internal conditions of the body that have to be regulated
. Internal body temperature
. Water levels
. Urea concentration
. Blood sugar levels
. Carbon dioxide levels
What three parts make up control systems
Coordination centers
Receptors
Effectors (muscles or glands)
Coordination centers
Coordination centers receive and process information arriving from receptor cells.
Receptors
Receptor cells detect changes in the environment.
Effectors
(muscles or glands) that carry out responses to stimuli (events or things) that help to restore optimum levels.
What is the Negative Feedback Loop
. An internal condition changes
. Change is detected
. Corrective mechanisms are activated
. internal conditions return to normal
. corrective mechanisms are deactivated
What is Positive Feedback
Positive feedback is the opposite of negative feedback. It makes a small change even bigger
How does the nervous system protect organisms from harm
The nervous system protects organisms from harm by responding to changes in the environment.
It does this by coordinating communication between different parts of organisms
What is the Nervous System made up of
. The brain
. The Spinal cord
. Neurones
The Brain
The brain is one of the components (parts) of the central nervous system (CNS).
The CNS coordinates the response of effectors.
Effectors are muscles or glands that act in response to a change in the internal or external environment.
The Spinal Cord
The spinal cord is the other component (part) of the CNS. It is also important in coordinating the response of effectors to changes in the environment.
Neurones
Neurones (nerve cells) carry electrical impulses (signals) between receptors, the central nervous system (CNS) and effectors.
What are Synapses
Synapses are gaps between neurones, and can be found at each junction of a reflex arc. Nerve impulses need to travel across synapses:
Arrival at the Synapse
The electrical impulse reaches the end of the neurone before the synapse.
This triggers the release of chemicals called neurotransmitters.
Passing on the Impulse
The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
The neurotransmitters bind to receptors on the next neurone.
The presence of the neurotransmitter causes the production of an electrical impulse in the next neurone.
What are reflexes
Reflex actions allow us to respond to dangerous situations rapidly and automatically. Reflex actions do not involve conscious thought
What are some examples of reflexes
. Sneezing
. Blinking
. Dropping hot objects
How does the central nervous system respond to stimuli
Via the reflex arc
What are the components of the reflex arc
. Stimulus
. Receptor
. Neurones
. Effector
. Response
Stimulus
A stimulus can be any change in the environment to which the body needs to respond.
The stimulus is detected by a receptor.
Receptor
Receptors are found all over the body.
They detect the change in the environment and initiate (start) a signaling process within the body.
The signal is picked up by a neurone (nerve cell).
What are the three types of Neurone
. Sensory Neurone
. Relay Neurone
. Motor Neurone
Sensory Neurone
carries the signal in the form of an electrical impulse to the central nervous system (CNS)
Relay Neurone
relays the electrical impulse from the sensory neurone to the appropriate motor neurone