What is system integration in living organisms?
Enjoying Flashcards?
Tell us what you think
What is system integration in living organisms?
System integration refers to the coordination of different parts of a body system to work together effectively, ensuring that all systems of a complex organism function harmoniously.
How do cells communicate within and between different body systems?
Cells communicate using mechanisms such as hormones, which are produced in one body system and can affect cells in a different system elsewhere in the organism.
What is the hierarchy of organisation in multicellular organisms?
The hierarchy of organisation in multicellular organisms includes cells forming tissues, tissues forming organs, organs forming organ systems, and organ systems working together to support the whole organism.
What are emergent properties in multicellular organisms?
Emergent properties are new functions and abilities that arise when individual cells and systems work together, allowing multicellular organisms to perform tasks that unicellular organisms cannot, like complex movement and digestion.
What are the two main systems of communication in animals?
The two main systems of communication in animals are the nervous system, which uses electrical impulses, and the endocrine system, which uses hormones to regulate body processes.
How do the nervous system and endocrine system work together?
The nervous system and endocrine system often work together to maintain processes like digestion, heart rate, and blood pressure by coordinating the transfer of energy and materials throughout the body.
What is the function of the nervous system?
The nervous system consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves). It allows organisms to sense their surroundings, respond to stimuli, and regulate body functions.
What is the function of the endocrine system?
The endocrine system produces hormones through glands, which are then transported in the blood to target organs, where they regulate long-term processes that do not require instant responses.
How do hormones affect target cells?
Hormones affect only cells with specific receptors that match the hormone. When hormones bind to these receptors, they can bring about changes in the activity of the target cells or organs.
Compare the response time between the nervous system and endocrine system.
The hormones that travel in the blood transmit the signals slower than impulses in the nervous system, however the nervous system response tends to be short lived compared to longer lived responses from the endocrine system.
What is the role of the brain in the central nervous system?
The brain, along with the spinal cord, forms the central nervous system and is responsible for controlling complex behaviours, both conscious and unconscious, by processing and coordinating information.
What functions are associated with the cerebral cortex?
The cerebral cortex, the highly folded outer layer of the brain, is responsible for higher-order processes such as intelligence, memory, consciousness, and personality.
What is the role of the cerebellum?
The cerebellum, located underneath the cerebral cortex, is responsible for balance, muscle coordination, and movement.
What is the brainstem's function?
The brainstem relays messages between the cerebral cortex, cerebellum, and spinal cord, with the medulla, a key part of the brainstem, controlling unconscious activities like heart rate and breathing.
What are the roles of the pituitary gland and the hypothalamus?
The pituitary gland produces hormones, including those that control the menstrual cycle (FSH and LH), while the hypothalamus regulates body temperature and produces hormones that control the pituitary gland.
What types of receptors provide input to the brain at a conscious level?
Conscious input to the brain is provided by photoreceptors in the eyes (for vision), chemoreceptors in the tongue (for taste), thermoreceptors in the skin (for temperature), and mechanoreceptors in the inner ear (for sound vibrations).
What types of receptors provide unconscious input to the brain?
Unconscious input is provided by osmoreceptors (detecting blood water content), baroreceptors (sensing blood pressure changes), and proprioceptors (providing information on balance and movement).
What is the spinal cord’s role in the central nervous system?
The spinal cord acts as a neural pathway between the body and the brain, processing sensory information and enabling motor responses. It also serves as an integration centre for unconscious processes and reflex reactions.
What is the difference between white matter and grey matter in the spinal cord?
White matter contains the axons of neurons that carry information to and from the brain, while grey matter contains neurons and synapses involved in spinal cord integration processes, creating reflex responses.
What is the role of a receptor in a neural pathway?
A receptor is a specialised cell that detects changes in the environment, which cause a stimulus.
How do receptor cells function as transducers?
Receptor cells convert energy in one form (e.g. light, heat, or sound) into electrical impulses within a sensory neurone, allowing the nervous system to process environmental changes.
Where are receptor cells typically found?
Receptor cells are often found in sense organs, such as light receptors in the eyes or chemoreceptors in the taste buds.
What happens when receptor cells are stimulated?
When receptor cells are stimulated, they become depolarised. If the stimulus is strong enough, this depolarisation triggers an action potential in the sensory neurone, transmitting the impulse to the CNS.
Describe the sequence of events that occurs when chemoreceptors in the taste buds detect salt.
When chemoreceptors in the taste buds detect salt:
Sodium ions from the salt diffuse through channel proteins in the microvilli of chemoreceptor cells, leading to membrane depolarisation
This depolarisation triggers calcium ion channels to open, causing neurotransmitter release
This then initiates an action potential in the sensory neurone
Transmitting the impulse to the brain
What is the function of motor neurones?
Motor neurones carry action potentials from the CNS to effectors (muscles and glands), initiating the required response e.g. hormone release or movement.
Where do motor neurones terminate?
Motor neurones can terminate at neuromuscular junctions, which are connections between the motor neurone and a muscle cell.
How does transmission occur across a neuromuscular junction?
When an impulse arrives at the motor neurone's presynaptic membrane, it causes calcium ions to enter the neurone. This leads to the release of acetylcholine (ACh), which diffuses across the junction, binds to receptor proteins on the muscle cell, and triggers an action potential that leads to muscle contraction.
What is the role of calcium ions in muscle contraction?
Calcium ions, released from the sarcoplasmic reticulum in response to an action potential, bind to troponin molecules on the actin filaments. This causes the troponin-tropomyosin complex to shift, exposing binding sites on the actin for myosin, thus initiating muscle contraction.
What is myelination, and why is it important?
Myelination refers to the presence of a myelin sheath around the axons of neurones, which speeds up the transmission of nerve impulses along the neurone. Myelinated neurones transmit impulses faster than unmyelinated ones.
What is a reflex?
A reflex is an action of the body that occurs without conscious thought.
True or False?
Reflexes are automatic and rapid, minimising damage to the body.
True.
Reflexes are automatic and rapid, minimising damage to the body.
Define the term reflex arc.
A reflex arc is a pathway along which impulses are transmitted from a receptor to an effector without involving conscious regions of the brain.
What is a nociceptor?
A nociceptor is a pain receptor that detects harmful stimuli like a sharp pin or hot flame.
State the order of a pain reflex arc.
The order of a pain reflex arc is: nociceptor → sensory neurone → relay neurone → motor neurone → effector muscle.
What does the pupil reflex do?
The pupil reflex prevents damage to the eye from bright light.
What is the function of the cerebellum?
The cerebellum coordinates movement, including balance, posture, walking, hand and finger movements, eye movements, and speech.
True or False?
The cerebellum initiates movement in the body.
False.
The motor cortex of the cerebrum initiates movement, not the cerebellum.
What is melatonin?
Melatonin is a hormone secreted by the pineal gland that regulates circadian rhythms, including the sleep-wake cycle.
True or False?
Circadian rhythms in humans are influenced by melatonin.
True. Circadian rhythms in humans are influenced by melatonin.
Define circadian rhythm.
A circadian rhythm is a daily cycle of physiological and behavioural patterns that occur in a 24-hour period.
State the effect of increasing melatonin levels.
Increasing melatonin levels lead to feelings of tiredness and promote sleep.
State the role of light in regulating melatonin production.
Light resets the melatonin system daily, keeping the circadian rhythm aligned with daylight hours.
What is the function of the pineal gland related to circadian rhythms?
The pineal gland secretes melatonin, which regulates circadian rhythms by responding to light and dark signals.
What role does epinephrine play in the body?
Epinephrine prepares the body for reacting to a stressful situation, often called the "fight or flight" response.
True or False?
Epinephrine decreases heart rate during stressful situations.
False.
Epinephrine increases heart rate during stressful situations.
What is meant by the term "fight or flight response"?
The "fight or flight" response is the body's reaction to stress, fear, or excitement, preparing it for vigorous activity.
What happens to blood vessels in less important organs during the "fight or flight" response?
Blood vessels in less important organs constrict to divert more blood to organs involved in the "fight or flight" response.
What is a hormone?
A hormone is a chemical messenger produced by an endocrine gland and carried by the blood.
True or False?
The hypothalamus controls the release of hormones from the pituitary gland.
True. The hypothalamus controls the release of hormones from the pituitary gland.
What is the role of the hypothalamus in osmoregulation?
The hypothalamus monitors the water balance of the blood and releases ADH if the blood becomes too concentrated.
State the function of the pituitary gland.
The pituitary gland produces and releases hormones that regulate various bodily processes and stimulates other endocrine glands.
True or False?
The medulla controls the heart rate through conscious activities.
False.
The medulla controls the heart rate through unconscious activities.
Define baroreceptor.
A baroreceptor is a pressure receptor that monitors changes in blood pressure, located in the aorta and carotid arteries.
What neurotransmitter is released by sympathetic neurones to increase heart rate?
Norepinephrine is released by sympathetic neurones to increase heart rate.
What happens when the acceleratory centre is activated?
When the acceleratory centre is activated, impulses are sent to the SAN, leading to an increased heart rate.
Define chemoreceptor.
A chemoreceptor is a sensor that detects changes in blood pH, oxygen, and carbon dioxide levels.
What controls ventilation rates in the body?
Ventilation rates in the body are controlled by respiratory centres located in the medulla of the brain.
True or False?
During exercise, the production of carbon dioxide increases due to increased respiration.
True.
During exercise, the production of carbon dioxide increases due to increased respiration.
What is carbonic anhydrase?
Carbonic anhydrase is an enzyme in red blood cells that catalyses the reaction between carbon dioxide and water to form carbonic acid.
What is the role of chemoreceptors in ventilation?
Chemoreceptors detect changes in blood pH caused by hydrogen ions and send action potentials to increase ventilation rates.
State the equation for the formation of carbonic acid in red blood cells.
The equation is:
CO₂ + H₂O ⇌ H₂CO₃
carbon dioxide + water ⇌ carbonic acid
True or False?
The enteric nervous system (ENS) controls peristalsis in the digestive system.
True.
The enteric nervous system (ENS) controls peristalsis in the digestive system.
Define peristalsis.
Peristalsis is a series of muscle contractions that pass like a wave along the alimentary canal, moving food through the digestive system.
What triggers the peristaltic reflex?
The peristaltic reflex is triggered by the detection of the bolus of food by stretch receptors in the alimentary canal.
State the function of circular muscles during peristalsis.
Circular muscles contract to reduce the diameter of the alimentary canal, preventing food from moving backwards.
What happens to smooth muscle ahead of the bolus during peristalsis?
Smooth muscle ahead of the bolus relaxes, opening the lumen of the alimentary canal to allow food to move forward.