Topic 6A Stimuli and Response Flashcards
What is the difference between sensory neurons, motor neurons, and interneurons?
~Sensory neurons: Transmit information from sensory receptors to the central nervous system (CNS).
~Motor neurons: Transmit impulses from the CNS to muscles or glands.
~Interneurons: Found in the CNS, they connect sensory and motor neurons and process information.
What is a synapse?
A synapse is the junction between two neurons where neurotransmitters are released to transmit electrical signals across the gap.
What is the role of neurotransmitters?
Neurotransmitters are chemical messengers that transmit signals across a synapse, allowing neurons to communicate with each other or with muscles and glands.
How do nerve impulses travel?
Nerve impulses travel as electrical signals along neurons, and they are passed from one neuron to the next across synapses using neurotransmitters.
What are tropisms in plants?
Tropisms are directional growth responses of plants to environmental stimuli, such as light (phototropism), gravity (gravitropism), and water (hydrotropism).
What is phototropism?
Phototropism is the growth of a plant toward light, driven by the hormone auxin, which accumulates on the shaded side of the plant, causing it to bend toward the light.
What is gravitropism?
Gravitropism (or geotropism) is the growth response of a plant to gravity, with roots growing downward (positive gravitropism) and stems growing upward (negative gravitropism).
How do animals respond to stimuli?
Animals respond to stimuli through their nervous and endocrine systems, using sensory organs to detect changes in the environment and initiating motor responses through muscles or glands.
What is reflex action?
A reflex action is an automatic, rapid response to a stimulus that involves a direct pathway (reflex arc) through the spinal cord without the involvement of the brain.
What is a receptor?
A receptor is a specialized cell or protein that detects a specific stimulus, such as light, heat, sound, or pressure, and converts it into an electrical signal.
What are sensory receptors?
Sensory receptors are cells that detect environmental stimuli, such as photoreceptors (light), thermoreceptors (temperature), and mechanoreceptors (pressure).
What are effectors?
Effectors are muscles or glands that carry out a response to a stimulus, such as contracting to move a muscle or secreting a hormone.
How do photoreceptors work in vision?
Photoreceptors in the retina (rods and cones) detect light and convert it into electrical signals that are sent to the brain for processing and visual perception.
What is the role of the medulla in controlling heart rate?
The medulla in the brain detects changes in blood pressure and oxygen levels and sends signals via the autonomic nervous system to adjust the heart rate accordingly.
How does the autonomic nervous system affect heart rate?
The autonomic nervous system controls heart rate through the sympathetic nervous system, which increases heart rate, and the parasympathetic nervous system, which decreases heart rate.
How does adrenaline affect heart rate?
Adrenaline, released during stress or excitement, stimulates the heart to beat faster and stronger, increasing heart rate and blood flow to muscles.
What is the electrical conduction system of the heart?
The electrical conduction system involves the sinus node (pacemaker), atrioventricular node (AV node), bundle of His, and Purkinje fibers, which coordinate the contraction of the heart muscle.
What is the Nervous System?
A network of neurons that transmits electrical impulses to coordinate and control responses to stimuli in the body.
What are Sensory Neurons?
Neurons that carry electrical impulses from sensory receptors to the central nervous system (CNS).
What are Motor Neurons?
Neurons that transmit electrical impulses from the CNS to muscles or glands, enabling movement or secretion.
What is a synapse?
A junction between two neurons, where neurotransmitters are released to transmit signals from one neuron to the next.
What are neurotransmitters?
Chemical messengers that transmit signals across synapses in the nervous system.
What is Tropism?
A directional growth response of plants to an environmental stimulus, such as light, gravity, or water.
What is Phototropism?
The growth of plants in response to light, typically causing them to bend toward the light source.
What is Gravitropism?
The growth response of plants to gravity, where roots grow downward and stems grow upward.
What is a Reflex Action?
An automatic and rapid response to a stimulus, mediated by a reflex arc through the spinal cord, without involvement of the brain.
What are receptors?
Specialised cells or proteins that detect environmental stimuli and convert them into electrical signals.
What are Sensory Receptors?
Cells that detect stimuli, such as light, sound, temperature, and pressure, and convert them into electrical signals.
What are effectors?
Muscles or glands that carry out a response to a stimulus.
What is the Sinus Node (Pacemaker)?
A group of cells in the right atrium of the heart that initiate electrical impulses to regulate the heart rate.
What is the Autonomic Nervous System?
Part of the nervous system that controls involuntary actions, including heart rate, digestion, and respiratory rate.
What is the medulla?
Part of the brainstem that regulates involuntary functions like heart rate, breathing, and blood pressure.
What is adrenaline?
A hormone released by the adrenal glands during stress that increases heart rate, blood pressure, and energy levels.
What is the electrical Conduction System of the Heart?
A network of specialized cells that coordinate the heartbeat by transmitting electrical impulses through the heart.
