Lecture 2: Organ Systems & Musculoskeletal System Basics

A set of Q&A flashcards covering key concepts from Lecture 2: Organ Systems & Musculoskeletal System Basics, including homeostasis, feedback mechanisms, and anatomy/functions of major organ systems.

What is the negative feedback mechanism?

A control process where a stimulus causes a change detected by receptors (internal or external), which signals a control center to activate an effector that returns the body toward its normal homeostatic range.

What is the positive feedback mechanism and give an example.

A mechanism that amplifies a stimulus; an example is childbirth, where uterine contractions reinforce further contractions.

Name the two major control/communication systems of the body.

The nervous system and the endocrine (hormonal) system.

What structures comprise the nervous system?

Brain, spinal cord, and nerves.

How do endocrine signals travel through the body?

Hormones are released by glands and travel through the bloodstream to their target organs.

What is the function of the reproductive system?

To produce gametes for sexual reproduction and support offspring development; many reproductive organs also have hormonal roles.

What is the function of the integumentary system?

To protect the body, act as a barrier, help retain body fluids, regulate temperature, and participate in immune defense.

What does the skeletal system do?

Provides shape and support, protects organs, enables movement with the muscular system, produces blood cells, and stores minerals.

What does the muscular system do?

Enables movement and posture by contracting skeletal muscles; muscles attach to bones via tendons; most are voluntarily controlled.

What is the primary role of the circulatory (cardiovascular) system?

To circulate blood, delivering oxygen and nutrients to cells and removing wastes, thus coordinating tissue perfusion.

What is the role of the lymphatic system?

Part of the immune system; transports lymph, assists in immune defense, and works with the cardiovascular system to monitor pathogens.

What is the primary function of the respiratory system?

Gas exchange: delivering oxygen to the blood and removing carbon dioxide; also supports speech and pH balance.

What is the purpose of the digestive system?

To break down food into nutrients that cells can use to produce energy (ATP).

What does the urinary (excretory) system regulate?

Water balance and electrolyte concentrations; removes waste products from the blood; urine is stored in the bladder and excreted via the urethra.

What is the Musculoskeletal System (MS) and why is it often considered together?

The combination of the muscular and skeletal systems; they cooperate for movement and posture and are often studied as the musculoskeletal system.

What components compose the skeletal system?

Bones, cartilage, and joints (with bone marrow producing blood cells and minerals stored in bone).

What are tendons and what is their role?

Dense connective tissue that attaches muscle to bone and transmits the force of contraction to the skeleton.

What is meant by origin and insertion in a muscle?

Origin is the attachment to the stationary bone; insertion is the attachment to the moving bone during contraction.

What are agonist and antagonist muscles?

An agonist is the muscle that contracts to produce a movement, while the antagonist relaxes to allow the movement (e.g., biceps vs. triceps).

Which muscles are voluntary and which are involuntary?

Skeletal muscles are voluntary; cardiac and smooth muscles are involuntary.

Why is the nervous system important for contraction?

Skeletal muscle contraction requires electrical impulses from the somatic motor nervous system; other muscles can contract without direct nervous input but are coordinated by the nervous system.

Why is perfusion important for the musculoskeletal system?

Adequate blood flow delivers oxygen and nutrients to muscles and bones and removes wastes, supporting movement and function.

Which organ systems are primarily involved in movement and posture?

Muscular and skeletal systems, collectively the musculoskeletal system.

What is the role of ATP in muscle contraction?

ATP provides the energy required for muscle fibers to contract (cross-bridge cycling) and for relaxation when the contraction ends.

What happens during muscle relaxation?

The muscle stops contracting and exerts no active force on the bones; it lengthens if external forces act on it.

How can a muscle lengthen after contracting?

External resistance (weight, gravity, or other opposing forces) causes the muscle to lengthen as it relaxes.

What are the two major functions of antagonistic muscle pairs?

One muscle (the agonist) contracts to produce a movement, while its partner (the antagonist) relaxes or lengthens to allow the movement.

What is the role of the nervous system in maintaining movement and health?

It coordinates, controls, and modulates muscles and organ systems; problems in the somatic motor nerves can disrupt movement (e.g., cerebral palsy, ALS).

What is the structural hierarchy in biology from smallest to largest?

Tissues form organs, organs form organ systems, and organ systems form the whole organism.

How many organ systems are in the human body?

Eleven organ systems.

What is the role of the skin in immunity?

The integumentary system acts as a barrier and first line of defense in the immune system.

Which endocrine glands are explicitly mentioned and what do they do?

Glands like the pituitary and thyroid secrete hormones into the bloodstream to regulate mood, growth and development, and metabolism.

What is homeostasis?

The maintenance of a stable internal environment in the body.

What is the relationship between organs, organ systems, and the organism?

Organs are tissues organized for specific functions; organ systems are groups of organs working toward a common goal; organ systems together sustain the organism.