C3.1 Integration of Body Systems (Questions)

What is system integration in organisms?

System integration is the coordination between and within multiple systems and interdependent subsystems to perform various functions of life.

What are the two primary systems used for internal communication in the body?

The endocrine system, which releases hormones, and the nervous system, which transmits nerve impulses.

How do cells within a multicellular organism interact?

Cells interact at multiple levels in a hierarchy of organization, forming tissues, organs, and organ systems.

What are tissues?

Tissues are groups of specialized cells that work together to perform specific functions.

What is the role of AT1 cells in the lungs?

AT1 cells make up 95% of the respiratory surface and are thin to allow for gas diffusion.

What is the function of AT2 cells in the lungs?

AT2 cells secrete surfactant to prevent the collapse of alveoli.

How do plant and animal cells adhere to each other?

Plant cells use a middle lamella rich in pectin, while animal cells use transmembrane proteins for strong links.

What is an organ?

An organ is a group of tissues that work together to carry out a specific function of life.

Give an example of an organ and its function.

The kidney is an organ of excretion.

What is an organ system?

An organ system is a group of organs that interact to perform an overall function of life.

How many organ systems are recognized in humans?

There are 11 recognized organ systems in humans.

What is an organism?

An organism is a living individual made up of interconnected parts, including organ systems, organs, tissues, and cells.

What is the role of the brain in the body?

The brain is the central integrating organ that receives, processes, stores information, and sends instructions to coordinate life processes.

What is memory in the context of the brain?

Memory is the capacity to store information for short or long-term use, essential for learning.

What are the two main types of tissues in the spinal cord?

White matter, which contains myelinated axons, and grey matter, which contains cell bodies of motor neurons and interneurons.

What is the function of white matter in the spinal cord?

White matter conveys signals from sensory receptors to the brain and from the brain to the body's organs.

What is the function of grey matter in the spinal cord?

Grey matter processes information and is involved in decision-making.

What is the significance of feedback mechanisms in body systems?

Feedback mechanisms, both negative and positive, facilitate communication and regulation between components of body systems.

What is the circulatory system's role in the body?

The circulatory system transports materials and energy between organs, supplying cells with oxygen and nutrients while removing waste.

How do organs in an organ system typically interact?

Organs in an organ system may be physically linked or dispersed, working together to perform specific functions.

What are emergent properties in the context of organisms?

Emergent properties are characteristics that arise from the interaction of parts within an organism, which cannot be predicted by studying components in isolation. (Viewed as a whole).

What is the function of the spinal cord as an integrating center?

The spinal cord integrates signals and processes information for unconscious reflexes and responses.

What is the importance of communication between cells in tissues?

Communication allows for coordinated functions, such as growth regulation in plants and electrical impulse transmission in heart muscle.

What role does the spinal cord play in the nervous system?

The spinal cord acts as an integrating centre for processing information and decision-making, particularly for unconscious processes like reflexes.

How does the spinal cord coordinate reflexes?

The spinal cord coordinates reflexes quickly, often faster than if signals were sent to the brain.

What types of stimuli do sensory receptors respond to?

Sensory receptors respond to external stimuli such as touch and heat, as well as internal conditions monitored by receptors like stretch receptors and chemoreceptors.

What are stretch receptors and their function?

Stretch receptors in striated muscle sense contraction states, allowing the brain to deduce body posture.

What do chemoreceptors detect?

Chemoreceptors in blood vessel walls detect concentrations of oxygen, carbon dioxide, and glucose.

How are signals from sensory receptors conveyed to the central nervous system?

Signals are conveyed as nerve impulses through sensory neurons, which have axons that vary in length depending on the distance to the brain or spinal cord.

What is the primary role of the cerebral hemispheres?

The cerebral hemispheres control striated muscles and certain glands, sending signals via motor neurons.

What is the primary motor cortex responsible for?

The primary motor cortex sends signals to striated muscles for voluntary movements, such as standing up.

What is a nerve?

A nerve is a bundle of nerve fibres enclosed in a protective sheath, containing both sensory and motor neurons.

What is the function of motor neurons?

Motor neurons transmit impulses to effectors, such as muscles and glands, to carry out responses to stimuli.

What is a reflex action?

A reflex action is a rapid, involuntary response to a specific stimulus, coordinated by the nervous system.

What are the components of a reflex arc?

A reflex arc consists of receptors, sensory neurons, interneurons, motor neurons, and effectors.

How do interneurons function in reflex actions?

Interneurons process signals from sensory neurons and make decisions about appropriate responses, often connecting sensory and motor neurons.

What types of effectors respond to motor neuron signals?

Effectors can be muscles, which contract, or glands, which secrete in response to signals from motor neurons.

Cells within a multicellular organism interact with each other at multiple levels in a hierarchy of organization:

Cell → Tissue → Organ → Organ System → Organism

State:

One or two words

In a graph use:

→ Increase (high, positive)

→ Decrease (low, negative)

Outline:

One sentence, no explanation

Suggest: 

High-level question = Intepretation

Compare and contrast:

One difference and one similarity

Outline:

Brief/one sentence

What do sensory neurons convey to the central nervous system?

Sensory neurons convey signals from receptor cells and nerve endings that perceive stimuli directly in the form of nerve impulses.

How are nerve impulses carried to the brain or spinal cord?

Nerve impulses are carried along the axons of sensory neurons, which vary in length depending on the distance from the receptor cell to the CNS.

How long can the axons of sensory neurons be?

They can be a metre or more in length if the receptor cell is at the end of a toe.

Which main sense organs send their signals to the brain?

The eyes, ears, nose, and tongue are the main sense organs that send signals to the brain.

Where are sensory signals from the rest of the body received?

Signals from skin, muscles, and other organs are received by the spinal cord.

How are sensory inputs processed in the brain?

Sensory inputs are received by specialized areas in the cerebral hemispheres dedicated to processing different senses.

Where is the visual cortex located and what does it do?

The visual cortex is in the posterior part of the cerebrum and receives signals from rod and cone cells of the eyes.

Why do different sensory neurons have different axon lengths?

The length of the axons depends on the distance between the receptor cell and the brain or spinal cord, ensuring signals reach the CNS efficiently.

What is the major role of the cerebral hemispheres in the body?

The cerebral hemispheres control striated muscles and certain glands, regulating voluntary movements and some autonomic functions.

Which part of the cerebral hemispheres sends signals directly to striated muscles?

The primary motor cortex sends signals via motor neurons to each striated muscle in the body.

What is striated muscle, and where is it attached?

Striated muscle is attached to bone and is responsible for locomotion, posture control, and voluntary movements.

Can striated muscle be controlled consciously?

Yes, striated muscle can be controlled consciously, allowing intentional movements like standing up or walking.

What is an example of a movement controlled by the motor cortex?

Standing up from a sitting position, where signals from the motor cortex travel via motor neurons to leg muscles.

Through what pathway do signals travel from the motor cortex to the muscles?

Signals travel from the motor cortex through motor neurons to the corresponding striated muscles.

Why is the primary motor cortex important for posture and locomotion?

It sends precise signals to coordinate and contract the appropriate muscles required for movements and postural control.

What are the signals in motor neurons called?

Nerve impulses.

Where are the cell body and dendrites of many motor neurons located?

In the grey matter of the cerebral hemispheres.

What is the function of dendrites in motor neurons?

To receive signals from different relay neurons and transmit them to the cell body.

How many axons lead out from the cell body of a motor neuron?

One axon.

Where does the axon from the motor neuron cell body go?

Out of the brain and down the spinal cord to form a synapse with a second motor neuron.

What does the axon of the second motor neuron lead to?

One specific striated muscle.

How long can the combined axons of the two motor neurons extend?

Up to a metre or more, depending on muscle location.

How are motor neuron axons organized in the body?

They are bundled into nerves, often together with the axons of sensory neurons.

What happens when a nerve impulse reaches the end of a motor neuron axon?

It stimulates muscle fibres to contract and gland cells to secrete.

What is a nerve?

A nerve is a bundle of nerve fibres enclosed in a protective sheath.

What determines the size of a nerve?

The size of a nerve depends on the number of nerve fibres it contains and the proportion of fibres that are myelinated.

Which is the widest nerve in the human body?

The sciatic nerve, approximately 20 mm across.

How many nerve fibres are estimated to be in the optic nerve?

Between 770,000 and 1.7 million nerve fibres.

How many nerve fibres can small nerves contain?

Fewer than a hundred fibres.

Do most nerves contain both sensory and motor neurons?

Yes, most nerves contain fibres of both sensory and motor neurons.

Which nerve contains only sensory neurons?

The optic nerve.

Which nerve contains only motor neurons?

The oculomotor nerve.

Does every organ in the body receive nerve innervation?

Yes, all organs are served by one or more nerves.

In a sciatic nerve micrograph, what appears as dark blue circles?

Myelin sheaths surrounding axons.

What type of tissue is found around nerves and how is it stained in a micrograph?

Adipose (fat) tissue is found around the nerve, with fat droplets-stained dark brown.

What is a reflex action?

A reflex action is a rapid, involuntary response to a specific stimulus.

Why are reflexes considered the simplest type of coordination in the nervous system?

Because the signals pass through the smallest number of neurons, enabling faster responses.

What is the advantage of a rapid reflex response?

It helps prevent harm to the body by providing quicker reactions.

Which part of the nervous system coordinates reflexes like lifting your foot after treading on a sharp object?

The spinal cord coordinates such reflexes, known as spinal reflexes.

Which reflex is coordinated by the brain to protect the retina from damage?

Constriction of the pupil in response to bright light, a brain-coordinated reflex.

Can reflex actions occur without conscious thought?

Yes, reflex actions are involuntary and do not require conscious thought.

Give an example of a spinal reflex.

The pain reflex when lifting your foot after stepping on a sharp object.

Give an example of a brain-coordinated reflex.

The pupil constriction in response to bright light.

What is a reflex?

A reflex is an involuntary and nearly instantaneous movement in response to a stimulus, allowing the body to react without conscious thought.

Which nervous system component initiates a reflex?

Sensory (afferent) neurons detect the stimulus and send signals to the spinal cord or brain.

What part of the nervous system processes reflex signals?

The spinal cord or sometimes the brainstem processes reflex signals through interneurons in a reflex arc.

Which neurons carry the response from the spinal cord to effectors?

Motor (efferent) neurons transmit signals from the spinal cord to the muscles.

How do muscles participate in reflexes?

Muscles contract in response to motor neuron signals to produce the reflex action.

What role do bones and joints play in reflexes?

Bones and joints provide the mechanical support and leverage needed for muscles to move body parts quickly during reflexes.

What is the knee-jerk reflex an example of?

It is a simple reflex arc involving sensory input from a tendon, processing by the spinal cord, and motor output to the quadriceps muscle.

Why do reflexes not require conscious thought?

Because the reflex arc bypasses the brain's higher centers, allowing rapid responses to protect the body from injury.

How do the nervous, muscular, and skeletal systems work together in a reflex?

The nervous system senses and sends signals, the muscular system contracts to produce movement, and the skeletal system provides structure and leverage necessary for motion.

What is a receptor cell?

A receptor cell is a cell that senses a change in conditions, known as a stimulus.

How many types of stimuli can each receptor cell detect?

Each receptor cell detects only one type of stimulus.

Can sensory neurons perceive stimuli directly?

Yes, the nerve endings of some sensory neurons can perceive a stimulus directly without a separate receptor cell.

Which types of stimuli are detected directly by nerve endings in the skin?

Pain and heat are detected directly by nerve endings in the skin.