Biomechanics and Human Physiology Flashcards

Vocabulary study set covering mechanics of motion, nervous system communication, homeostatic mechanisms, and cardiovascular/respiratory measurements.

Speed

The rate at which an object covers distance. It is a scalar quantity, calculated as: $\text{Distance}/\text{Time}$.

Velocity

The speed of an object in a specific direction. It is a vector quantity, calculated as: $\text{Displacement}/\text{Time}$.

Acceleration

The rate of change of velocity per unit of time ($\text{Change in Velocity}/\text{Time}$). It can be positive (speeding up) or negative (decelerating).

Centre of Mass

The theoretical point at which all of the body’s mass is considered to be concentrated. It changes position depending on body posture and can lie outside the physical body(ex: during a high jump Fosbury Flop)

Linear Momentum

The property of a moving body determined by the product of its mass and velocity($\text{Momentum} = \text{Mass} \times \text{Velocity}$)

Impulse

The product of the force applied to a body and the time over which it is applied($\text{Impulse} = \text{Force} \times \text{Time}$). It is equal to the change in momentum.

Eccentric Force

A force applied outside or away from the center of mass of an object or body, which results in rotation(Angular Motion)

Angular Momentum

The amount of rotation of a body, which is the product of the moment of inertia and angular velocity($\text{Angular Momentum} = \text{Momentum of Inertia} \times \text{Angular Velocity}$). It remains constant when a body is airborne.

Coefficient of Restitution

A measure of the elasticity of bodies involved in a collision, calculated as the ratio of the relative velocity after a collision to the relative velocity before the collision(Ranging from $0$ to $1$, where was is $1$ is perfectly elasticity).

Static Friction

The frictional force that prevents two surfaces from sliding past one another when they are at rest(Must be overcome to initiate movement).

Dynamic Friction

The frictional force that acts between sliding surfaces once the object is in motion(Typically lower than static friction).

Work

The force exerted on an object times the distance it moves in the direction of that force($\text{Work} = \text{Force} \times \text{Distance}$). Measured in Joules($J$).

Power

The rate at which work is done or energy is transferred($\text{Power} = \frac{\text{Work}}{\text{Time}}$ or $\text{Force} \times \text{Velocity}$). Measured in Watts($W$).

Central Nervous System (CNS)

Composed of the brain and spinal cord; its primary function is to integrate and process sensory information and coordinate bodily reactions.

Peripheral Nervous System (PNS)

All the nerves outside the CNS that connect the brain and spinal to the rest of the body(muscles, organs, senses).

Afferent (Sensory) Neurons

Neurons that carry sensory impulses from receptors in the peripheral nervous system to the central nervous system.

Efferent (Motor) Neurons

Neurons that carry motor commands away from the CNS and to effector organs like skeletal muscles.

Autonomic Nervous System

A division of the PNS that unconsciously regulates involuntary physiological processes(ex: heart rate, digestion, breathing).

Somatic Nervous System

A division of the PNS associated with the voluntary control of body movements via skeletal muscles.

Sympathetic Nervous System

The branch of the autonomic nervous system that drives the “Fight or Flight” response, increasing heart rate, blood pressure, and metabolic rate during exercise or stress.

Parasympathetic Nervous System

The branch of the autonomic nervous system that helps lower the heart rate and help the body post exercise.

Proprioceptors

Sensory receptors located in muscles, tendons, and joints(ex: muscle spindles and Golgi tendon organs) that detect body position, muscle length, and tension.

Baroreceptors

Specialized pressure sensors located in blood vessels(like the carotid sinus and aortic arch) that monitor blood pressure and signal the brain to adjust it.

Chemoreceptors

Sensors that detect chemical changes in the blood, specifically monitoring variations in $\text{pH}$, carbon dioxide, and oxygen levels to adjust ventilation and heart rate.

Hormones

Chemical messengers secreted by endocrine glands directly into the bloodstream to regulate distant target organs and physiological processes(ex: adrenaline, insulin).

Homeostasis

The maintenance of a constant, stable internal environment within tolerable physiological limits despite external environmental changes.

Negative Feedback

A primary regulatory mechanism where a change in a physiological variable triggers a response that counteracts or reverses the initial change to restore balance.

Thermoregulation

The process by which the body maintains it core internal temperature within a safe range.

Vasodilation

The widening of blood vessels near the skin’s surface, increasing blood flow to allow heat loss to the environment(cooling mechanism).

Vasoconstriction

The narrowing of blood vessels near the skin’s surface, reducing blood flow to minimize heat loss and converse core warmth.

Acclimatization

The gradual physiological adaption of the body over days or weeks to a new environment, such as changes in altitude, temperature, or humidity, to optimize exercise performance.

Heart Rate

The number of times the heart beats per minute($\text{bpm}$).

Stroke Volume

The volume of blood pumped out of the left ventricle of the heart during a single contraction(average $70\,ml$).

Cardiac Output

The total amount of blood pumped by the heart per minute, calculated as(heart rate x stroke volume; $Q = HR \times SV$)

Sinoatrial (SA) Node

A specialized cluster of atrioventricular cells in the right atrium that generates electrical impulses to initiate heart contractions.

Atrioventricular (AV) Node

A specialized mass of conduction cells located between the atria and ventricles that delays the electrical impulse briefly to allow the atria to finish contracting before the ventricles pump.

Purkinje Fibres

Specialized nerve fibers in the ventricular walls that rapidly relay the electrical impulse from the AV node, causing coordinated contraction of the ventricles.

Minute Ventilation

The total volume of gas inhaled or exhaled from a person’s lungs per minute, calculated as Tidal Volume x Respiratory Rate($Ve = Vt \times Bf$).

Tidal Volume

The volume of air moved into or out of the lungs during a normal breath.

Vital Capacity

The total volume of that can be voluntarily moved in and out of the lungs.

Total Lung Capacity

The total amount of air the lungs can hold after maximum inhalation(Vital Capacity + Residual Volume).

Inspiratory Reserve Volume

The maximum volume of air that can be inhaled after a normal inhalation.

Expiratory Reserve Volume

The maximum volume of air that can be exhaled after a normal exhalation.

Residual Volume

The volume of air remaining in the lungs after a maximal exhalation.