Biology Homeostasis and Control Systems

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Questions and Answers

What is the primary reason rod cells provide low visual acuity?

Rod cells do not absorb different wavelengths of light.

Rod cells can only respond to high light intensity.

Multiple rod cells connect to a single bipolar cell. (correct)

Rod cells are located exclusively in the fovea.

Which type of cells allows the human brain to distinguish between separate light sources?

Bipolar cells

Cone cells (correct)

Rod cells

Peripheral cells

What happens to iodopsin in cone cells under low light conditions?

Iodopsin remains intact, preventing action potential generation. (correct)

Iodopsin is synthesized rapidly for color perception.

Iodopsin is broken down, causing color blindness.

Iodopsin loses its pigment properties.

What role does the fovea play in vision?

It is the area where light is focused and visual acuity is highest. Signup and view all the answers

Why do cone cells only respond to high light intensity?

Each cone cell connects to a single bipolar cell, allowing no spatial summation. Signup and view all the answers

What happens if the depolarisation does not exceed the -55 mV threshold?

Nothing happens, and no action potential is generated Signup and view all the answers

What does the all-or-nothing principle ensure regarding action potentials?

Only large stimuli can trigger responses Signup and view all the answers

During the refractory period, what occurs at the sodium channels?

They cannot be opened because they are recovering Signup and view all the answers

What primarily causes the depolarisation of the neurone during an action potential?

An influx of Na+ ions Signup and view all the answers

What is the immediate consequence of reaching the threshold of +40mV in the axon?

Sodium channels close Signup and view all the answers

What is one key function of the refractory period in nerve impulses?

It limits the frequency of action potentials being transmitted Signup and view all the answers

What is meant by 'discrete impulses' in the context of action potentials?

They are distinct signals that do not overlap Signup and view all the answers

What happens to the neurone’s voltage after potassium ion channels open during repolarisation?

It becomes more negative than the resting potential Signup and view all the answers

What role do voltage-gated channels play in the generation of a nervous impulse?

They open in response to changes in voltage Signup and view all the answers

Which sequence correctly describes the process following a stimulus in a neurone?

Voltage-gated sodium channels close, K+ exits, repolarisation occurs Signup and view all the answers

What would a woodlouse do when it crosses from a damp area to a dry area?

Turn rapidly to return to dampness Signup and view all the answers

What two systems make up the nervous system?

Central and peripheral Signup and view all the answers

What triggers the response in the nervous system according to the outlined process?

Receptor Signup and view all the answers

Which of the following receptors responds to pressure changes?

Pacinian corpuscle Signup and view all the answers

Where are Pacinian corpuscles primarily located in the body?

In the skin, mainly in fingers and feet Signup and view all the answers

What is a generator potential in the context of receptor response?

An electrical change in a neurone triggered by stimulation Signup and view all the answers

What role do channel proteins play in the Pacinian corpuscle?

They facilitate the generation of action potentials Signup and view all the answers

Which of the following statements about receptors is true?

Each receptor responds only to specific stimuli Signup and view all the answers

What is the role of pressure receptors in the aorta and carotid artery during high blood pressure?

To decrease the frequency of electrical impulses. Signup and view all the answers

What causes the increase in heart rate when blood pressure decreases?

Less stretch in pressure receptors leads to impulses sent via the sympathetic nervous system. Signup and view all the answers

Which part of the nervous system is involved when responding to low pH levels?

Sympathetic nervous system. Signup and view all the answers

What is the primary outcome of activating the SAN during low blood pressure events?

Increase in the frequency of electrical impulses. Signup and view all the answers

Which statement accurately describes the role of chemoreceptors?

They sense changes in the concentration of chemicals in the blood. Signup and view all the answers

What physiological change occurs as a response to increased heart rate?

Enhanced removal of carbon dioxide. Signup and view all the answers

How do the pacinian corpuscles function as receptors?

They detect pressure changes on the skin. Signup and view all the answers

Which primary physiological response occurs due to the detection of high blood pressure?

Decreased heart rate via the SAN. Signup and view all the answers

Where are most cone cells located in the eye?

Near the fovea Signup and view all the answers

What distinguishes rod cells from cone cells?

Rod cells respond better at lower light intensities Signup and view all the answers

What role does the sinoatrial node (SAN) play in the cardiac cycle?

It functions as a pacemaker for initiating contraction Signup and view all the answers

How does the atrioventricular node (AVN) contribute to heart contraction?

It releases a wave of depolarization after receiving signals from the SAN Signup and view all the answers

What function does the non-conductive layer serve in the cardiac conduction system?

It prevents the wave of depolarization from reaching the ventricles immediately Signup and view all the answers

What is meant by the term 'myogenic' in relation to cardiac muscle?

The muscle can initiate its own contractions Signup and view all the answers

What is the function of Purkyne fibers in the heart?

They transmit depolarization throughout the ventricles Signup and view all the answers

What is the primary function of cone cells in the visual system?

They allow for color vision and function in bright light Signup and view all the answers

Study Notes

Homeostasis is maintaining a constant internal environment in organisms.
Control systems maintain temperature, blood pH, blood glucose and water potential within limits.
Homeostasis is vital for enzyme function and metabolic reactions.
Negative feedback mechanisms return systems to their normal level when there is a deviation.
Blood glucose regulation involves the pancreas and its hormones insulin and glucagon to maintain blood glucose levels.
Osmoregulation control of water potential in the blood, involving the hypothalamus and posterior pituitary gland.
Maintaining blood water potential, too little water causes shrinkage and too much causes swelling of cells, so homeostasis is needed to maintain a balance.
ADH increases water permeability of the collecting duct in the kidney, increasing water absorption and making urine more concentrated.
Receptors are essential in detecting changes to trigger a response.

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Description

This quiz covers the essential concepts of homeostasis, including control systems for temperature, blood glucose, and water potential. Learn about the importance of negative feedback mechanisms in maintaining internal balance, and the role of hormones like insulin and ADH. Test your understanding of how organisms regulate their internal environment for optimal function.