Human Physiology Quiz

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Questions and Answers

What is the primary focus of physiology in relation to the body?

Investigating the history of medical practices

Understanding how the body maintains itself (correct)

Analyzing the effects of external environmental factors

Examining the genetic makeup of individuals

Which system is NOT included in the list of the 11 organ systems?

Endocrine

Circulatory

Respiratory

Neurological (correct)

What type of chemical messengers target cells in distant places?

Neurotransmitters

Cytokines

Hormones (correct)

Paracrine factors

In terms of cellular communication, which messenger acts primarily at a short distance?

Paracrine signals Signup and view all the answers

What is the standard oxygen requirement for survival in milliliters per kilogram per minute?

3.5 ml/kg/min Signup and view all the answers

What triggers the release of ATP during muscle contraction?

Binding of ATP to myosin Signup and view all the answers

Which type of muscle fiber is characterized by a high capacity for oxidative phosphorylation?

Type I fibers Signup and view all the answers

What effect does the binding of ATP to myosin have during muscle contraction?

It breaks the link between actin and myosin Signup and view all the answers

Which statement about Type IIx fibers is true?

They are fast-glycolytic fibers Signup and view all the answers

Which process is primarily responsible for energizing myosin during muscle contraction?

Hydrolysis of ATP Signup and view all the answers

What factor primarily influences the development of tension in muscle fibers?

The amount of tension developed by each fiber Signup and view all the answers

What occurs during tetanic muscle tension?

There is no time for the muscle to relax as fibers are recruited successively Signup and view all the answers

Which of the following is necessary for cross-bridge cycling to continue?

Calcium remaining bound to troponin Signup and view all the answers

How does the cytosolic Ca concentration change during muscle contraction?

It decreases as Ca-ATPase transports calcium back into the SR Signup and view all the answers

What is one condition that allows for quick bursts of muscle activity?

The characteristics of white muscle fibers Signup and view all the answers

What triggers the exposure of cross-bridge binding sites in muscle contraction?

Increased cytosolic calcium levels Signup and view all the answers

What role does ACh play in muscle contraction?

It increases permeability to sodium and potassium ions. Signup and view all the answers

Which process describes the movement of thin filaments during muscle contraction?

Thin filaments slide past thick filaments. Signup and view all the answers

In the sliding filament theory, what occurs when the muscle is relaxed?

There is no tension in the muscle fibers. Signup and view all the answers

What is the effect of action potential reaching the axon terminals?

It causes the release of ACh. Signup and view all the answers

Which statement correctly describes the end-plate potential (EPP)?

More sodium moves into the fiber than potassium moves out. Signup and view all the answers

What is the role of voltage-gated calcium channels during muscle contraction?

They allow calcium to enter the cytosol. Signup and view all the answers

How does tension relate to the frequency of stimulation in muscle fibers?

Tension increases with higher frequency of stimulation. Signup and view all the answers

What is the primary role of astrocytes in the central nervous system?

Regulate composition of extracellular fluid Signup and view all the answers

What characterizes a graded potential in neuronal activity?

It can occur without a threshold Signup and view all the answers

What condition involves involuntary muscle contraction due to low calcium levels?

Hypocalcemic tetany Signup and view all the answers

Which neurotransmitter is commonly associated with excitatory postsynaptic potentials (EPSPs)?

Acetylcholine Signup and view all the answers

What is the primary cause of muscle damage in rhabdomyolysis?

Muscle weakness and pain Signup and view all the answers

Which cells are known for performing immune functions in the central nervous system?

Microglia Signup and view all the answers

What is the function of the Na/K ATPase pump in maintaining resting membrane potential?

Establishes concentration gradients for sodium and potassium ions Signup and view all the answers

What results from an action potential reaching the axon terminal?

Release of neurotransmitters Signup and view all the answers

What is the rate of axon regrowth after a peripheral nerve injury?

1mm/day Signup and view all the answers

What distinguishes electrical synapses from chemical synapses?

They do not use neurotransmitters Signup and view all the answers

What defines hyperpolarization in neuronal activity?

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

Which isoenzyme of creatine kinase is primarily associated with damaged skeletal muscle?

CK-MM Signup and view all the answers

In synaptic transmission, what happens after neurotransmitters bind to postsynaptic receptors?

They may cause excitatory or inhibitory postsynaptic potentials Signup and view all the answers

What is the primary effect of GABA in the central nervous system?

Promotes hyperpolarization Signup and view all the answers

Which neurotransmitter is primarily responsible for excitatory synapses?

Glutamate Signup and view all the answers

What is the main role of myelin in neural communication?

Facilitates saltatory conduction Signup and view all the answers

What type of receptor does GABA bind to in the nervous system?

Ionotropic and metabotropic receptors Signup and view all the answers

Which of the following is a characteristic of the absolute refractory period?

No stimulus can trigger another action potential Signup and view all the answers

What consequence does a blockage of acetylcholinesterase lead to?

Enhanced muscle contraction Signup and view all the answers

What neurotransmitter is primarily involved in learning and memory processes?

Glutamate Signup and view all the answers

What effect does ethanol have on synaptic activity?

Stimulates GABA synapses Signup and view all the answers

Which condition results in flaccid paralysis due to reduced muscle contraction?

Clostridium botulinum infection Signup and view all the answers

What happens during hyperpolarization of a neuron?

Increased chloride influx Signup and view all the answers

Which neurotransmitter is primarily represented in digestive and immune systems?

Serotonin Signup and view all the answers

Strychnine acts as an antagonist for which neurotransmitter?

Glycine Signup and view all the answers

Which of the following is true regarding neuromodulators?

They modify the postsynaptic cell’s response Signup and view all the answers

Long-term potentiation is associated with which of the following processes?

Persistent changes in synaptic strength Signup and view all the answers

Study Notes

Homeostasis

Physiology is the study of how the body functions. It emphasizes the body's ability to maintain itself.
Body functions at different levels of organization work together.
There are 11 organ systems in the body.
Body fluid compartments include intracellular fluid (67%) and extracellular fluid (33%), with plasma comprising 7% of body fluid and interstitial fluid 26%.
Extracellular fluid has a high concentration of sodium and chloride ions. Intracellular fluid has a high potassium concentration.
Regulation is continuous and responsive to changes.
Chemical messengers such as hormones act on distant target cells. Paracrine substances act on neighboring cells and autocrine substances act on the same cell that released them.
Chemical disequilibrium occurs across selectively permeable membranes.
Homeostasis maintains a stable internal environment despite external changes. It's a dynamic condition, not equilibrium. A normal pH is 7.4.

Chemical Composition

Major elements (hydrogen, oxygen, carbon, nitrogen) make up 99.3% of the body's atoms.
Key minerals (7) and trace elements (13) make up 0.7% and <0.01% of the body's atoms, respectively.
Molecular shapes result from the possibility of rotation around different C-C bonds.
Amphipathic molecules have hydrophilic and hydrophobic parts.

Cells

Embryogenesis is the process of an embryo developing from an egg.
Spherical cell enlargement increases surface area by the square of cell size and volume by the cube of cell size.
Plasma membranes are a mixture of membrane proteins that can move in the lipid bilayer.
Three types of specialized membrane junctions include desmosomes (joining cells by strong proteins), tight junctions (impermeable membranes with no extracellular space) and gap junctions (protein channels that connect cytosols).
Cell organelles include the nucleus (largest, storing genetic info), nucleolus (inside the nucleus, involved in ribosome production), rough ER (protein synthesis), smooth ER (fatty acid and steroid synthesis), ribosomes (in rough ER), Golgi apparatus (modifies and sorts proteins), and mitochondria (produces ATP).

Solutes and Water

Water moves by osmosis, from low concentration to high solute concentration.
Movement of water passively can be aided by aquaporins.
Water movement depends on concentration gradients and requires no ATP.

Cells Signaling

Cells communicate via:
- Chemical signals
- Receptors in target cells
Ligands are secreted into extracellular fluid by cells.
Target cells have specific receptors that bind to these signals.
Responses vary depending on the target cell types.

Skeletal Muscle

Muscle contraction involves electrical/chemical signals.
Three types of muscles include skeletal, cardiac, and smooth muscle.
Sarcomere structure (relaxed = 2.6 μm, contracted = 1.6 μm) and components (actin, myosin, titin) are crucial.
Muscle fibers contract by the sliding filament theory. Interaction of actin-myosin filaments generates force.
ATP is essential. Types include slow-oxidative, fast-oxidative-glycolytic, and fast-glycolytic.

Neuromuscular Signaling

Neurons have dendrites, soma (cell body), axon (carries signals), axon hillock (generates action potentials), and axon terminals to release neurotransmitters.
Myelin sheaths (Schwann cells in PNS) speed up conduction.
Electrical and chemical synapses exist.
Neurotransmitters bind to receptors on postsynaptic neurons, leading to the generation of graded potentials.
Different types of neurons exist (e.g., sensory, motor, interneurons).
Synapses: electrical (direct flow), and chemical (release of NT which binds to receptors).

Nervous System

The CNS includes the brain (encephalon) and spinal cord. The PNS connects the CNS to the rest of the body.
Neurotransmitters such as ACh, norepinephrine, dopamine, GABA, glutamate, serotonin and histamine are involved in various types of communication and responses. Different types of neurons and glial cells contribute to the function of the nervous system.

Endocrine System

Hormones are secreted into the bloodstream by endocrine glands to target distant cells.
Hormones act directly on cells in the body.
Different hormones have different roles depending on the organs they affect.
Various hormones and their functions are discussed in terms of their structure, production and effect on the cell or organism.

Cardiovascular System

Blood contains erythrocytes for O2 transport and leukocytes for immune defense.
Hematocrit (ratio of red blood cells to total blood volume) can vary.
Cardiovascular system consists of a pump (heart) and a circulatory system for circulation of blood through the body.
Blood pressure and heart function are explained.

Respiratory System

Gases (O2, CO2) are exchanged between the air and blood in the lungs.
The lungs have specialized structures.
Pulmonary ventilation is measured. Factors influencing rate and volume include breathing rate and volume.
Movement of air is explained based on pressure differences.

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Description

Test your knowledge on human physiology and muscle function. This quiz covers topics such as organ systems, chemical messengers, muscle contraction dynamics, and cellular communication. Challenge yourself to see how well you understand the physiological processes in the human body!