Cuestionario: Introduction to Human Physiology — 12 preguntas

1. How do insulin and glucagon differ in their roles within blood glucose homeostasis?

A. Both increase blood glucose levels by stimulating the liver to release glucose.

B. Insulin and glucagon are hormones that are only active during physical activity.

C. Both are produced by the pancreas but regulate blood glucose in the same way.

D. Insulin lowers blood glucose levels, whereas glucagon raises them, by acting on the liver.

Answer: (D)

Explicación

Insulin decreases blood glucose levels by promoting uptake and storage of glucose, while glucagon increases blood glucose levels by stimulating the liver to release stored glucose. They have opposite effects, which is essential for maintaining blood glucose within a narrow range.

2. What is the primary role of the control center in the stimulus-response pathway?

A. Receives information from receptors and processes it

B. Carries out the body's response to stimuli

C. Detects stimuli and sends signals to effectors

D. Detects changes in the environment

Answer: (A)

Explicación

The control center in the stimulus-response pathway processes information received from receptors and determines the appropriate response. It acts as the processing unit, which is explicitly described in the source content.

3. What is the main role of different sensory receptor types in the body?

A. To produce hormones in response to stimuli

B. To transmit nerve signals from the brain to effectors

C. To detect specific environmental stimuli and convert them into nerve signals

D. To process and interpret sensory information in the brain

Answer: (C)

Explicación

Different sensory receptor types are specialized for detecting specific stimuli, such as light, touch, temperature, or chemicals, and converting these stimuli into nerve signals that can be interpreted by the brain. Their main purpose is stimulus detection, making option one the correct answer. The other options describe functions of neurons or the endocrine system, not the specific role of sensory receptor types.

4. Arrange the following neuron components in the order in which they transmit a nerve impulse during neural communication.

A. Axon, dendrites, cell body, synapse

B. Synapse, dendrites, cell body, axon

C. Dendrites, cell body, axon, synapse

D. Cell body, dendrites, axon, synapse

Answer: (C)

Explicación

The correct sequence of neuron components during neural transmission starts with dendrites detecting stimuli, followed by the cell body processing the signals, then the impulse travels along the axon, and finally reaches the synapse where neurotransmitters are released to pass the signal to the next neuron or effector.

5. What is the primary function of dendrites in a neuron?

A. Transmit electrical impulses away from the cell body

B. Receive signals from sensory receptors or other neurons

C. Insulate the axon to speed up signal transmission

D. Produce neurotransmitters to communicate with other neurons

Answer: (B)

Explicación

Dendrites are branched extensions of a neuron that receive messages from sensory receptors or other neurons, acting as the primary sites for signal reception. Transmitting impulses away from the cell body is the role of the axon, not dendrites. Insulation of the axon is performed by the myelin sheath, and neurotransmitter production occurs at the axon terminal, not dendrites.

6. In designing a neural pathway for a reflex that involves detecting a hot surface and pulling away quickly, which type of neuron should be involved in transmitting the initial signal from the skin to the spinal cord?

A. Sensory neuron

B. Motor neuron

C. Effector neuron

D. Interneuron

Answer: (A)

Explicación

The initial signal from a sensory receptor in the skin detecting heat should be transmitted by a sensory neuron, as its role is to carry nerve impulses from sensory receptors to the central nervous system for processing.

7. What is an action potential in the context of neural communication?

A. An electrical impulse that travels along a neuron, generated when a neuron reaches its threshold potential

B. A chemical messenger released at the synapse to transmit signals between neurons

C. The process of neurotransmitter synthesis in the neuron

D. A physical connection between neurons that allows direct electrical flow

Answer: (A)

Explicación

An action potential is an electrical impulse that travels along a neuron, generated when the neuron is sufficiently stimulated to reach its threshold potential. This impulse is fundamental to neural communication, enabling signals to be transmitted rapidly along neurons.

8. Who is credited with the understanding that reflex actions are rapid, involuntary responses mediated by the spinal cord?

A. William Harvey

B. Claude Bernard

C. Charles Sherrington

D. Johann Purkinje

Answer: (C)

Explicación

Charles Sherrington is credited with describing and understanding reflex actions as rapid, involuntary responses mediated by the spinal cord, which is a fundamental concept in neurophysiology.

9. What is a key consequence of the endocrine system's hormone secretion for the body's internal environment?

A. It produces electrical signals for communication within the nervous system

B. It directly controls voluntary movements of skeletal muscles

C. It regulates blood glucose levels through hormone signals

D. It causes rapid nerve impulses to muscles during reflex actions

Answer: (C)

Explicación

The endocrine system's primary effect on the internal environment involves regulating processes such as blood glucose levels via hormones like insulin and glucagon. This hormonal regulation is crucial for maintaining homeostasis. The other options relate to nervous system functions, not the endocrine system, making them incorrect in this context.

10. How do hormones and target cells differ in their roles within the endocrine system?

A. Hormones are the receptors on cells that detect signals, while target cells are the hormones that trigger responses.

B. Hormones are produced by target cells, while target cells are the organs that secrete hormones.

C. Hormones are chemical messengers that travel through the bloodstream, whereas target cells are the cells that have specific receptors to respond to those hormones.

D. Hormones are the specific cells that respond to signals, while target cells are the glands that produce hormones.

Answer: (C)

Explicación

Hormones are chemical messengers secreted into the bloodstream to travel to specific cells, called target cells, which have receptors for those hormones. Target cells respond to the hormones by initiating a physiological change. The other options incorrectly describe the roles of hormones and target cells.

11. Which hormones are primarily responsible for regulating blood glucose levels?

A. Adrenaline

B. Insulin and glucagon

C. Growth hormone

D. Testosterone

Answer: (B)

Explicación

Insulin and glucagon are the key hormones secreted by the pancreas that regulate blood glucose levels. Insulin decreases blood glucose by promoting uptake into cells, while glucagon raises blood glucose by stimulating the liver to release stored glucose.

12. What is the primary purpose of the body's immune response when encountering pathogens and microorganisms?

A. To neutralize all substances in the blood

B. To promote the growth of beneficial microorganisms

C. To defend the organism by fighting off infection

D. To cause the destruction of the body's own cells

Answer: (C)

Explicación

The main role of the immune response is to protect the organism by identifying and fighting off invading pathogens and microorganisms, preventing disease and maintaining health.