Skeletal Muscle Flashcards
What is the basic unit of skeletal muscle?
Muscle Fiber
Each muscle fiber is an elongated cell composed of myofibrils.
What are the three types of connective tissue covering muscle?
- Epimysium
- Perimysium
- Endomysium
These connective tissues cover the entire muscle, each fascicle, and each muscle fiber respectively.
What is the sliding filament theory?
A theory that explains muscle contraction where actin and myosin filaments slide past each other, shortening the sarcomere.
What are the types of muscle fibers?
- Type I (Red/Slow)
- Type IIa (Red/Fast)
- Type IIb (White/Fast)
These classifications are based on their contraction speed and energy usage.
What is muscle tone?
The continuous and passive partial contraction of the muscles, helping maintain posture.
What is the primary energy source for muscle contraction?
Adenosine triphosphate (ATP)
ATP is essential for the mechanical work of muscle contraction.
How much body heat is produced by muscle contractions?
As much as 70% of body heat.
What are the four heart valves?
- Mitral valve
- Tricuspid valve
- Aortic valve
- Pulmonary valve
These valves control blood flow through the heart.
What is the function of the conduction system of the heart?
To initiate impulses and conduct them rapidly, coordinating the contractions of cardiac chambers.
What is the cardiac cycle?
The sequence of events in the heart from one heartbeat to the next, including contraction and relaxation phases.
Fill in the blank: The _______ is a specialized structure that connects the sarcolemma to the sarcoplasmic reticulum.
T tubule
What is the role of calcium ions in muscle contraction?
Calcium ions bind to troponin, causing a conformational change that exposes binding sites on actin.
True or False: Action potentials are considered an all-or-none response.
True
What are the components of a sarcomere?
- A bands
- I bands
- H zone
- Z line
- M line
These structures are essential for muscle contraction and are defined by the arrangement of actin and myosin.
What is the importance of blood supply to the heart?
It provides oxygen-rich blood to the heart muscle, essential for its function.
What is the significance of the neuromuscular junction?
It is the site where motor neuron axon terminals communicate with muscle fibers, leading to muscle contraction.
What happens during the depolarization phase of an action potential?
Ion gates open, allowing sodium ions to enter, making the inside of the cell positive.
List the factors affecting heart rate.
- Age
- Fitness level
- Autonomic nervous system
- Hormones
These factors can increase or decrease heart rate based on physiological needs.
What is the role of acetylcholine in muscle contraction?
It binds to receptors on the sarcolemma, initiating depolarization and triggering an action potential.
What happens during muscle fatigue?
Depletion of energy sources and accumulation of metabolic byproducts reduce muscle performance.
What occurs first in the cardiac cycle?
Atrial contraction occurs first
What does the conducting system provide to the heart?
The automatic rhythmic beat
What are the two main coronary arteries that branch off from the aorta?
Right coronary artery and left coronary artery
What is the cardiac cycle?
The sequence of mechanical and electrical events that repeats with every heartbeat
What are the two phases of the cardiac cycle?
- Systole
- Diastole
What is the period of contraction in the cardiac cycle called?
Systole
What is the period of relaxation in the cardiac cycle called?
Diastole
What does atrial systole contribute to the filling of the ventricles?
20–30 percent of filling
What does the term ‘atrial kick’ refer to?
Atrial contraction that contributes to ventricular filling
What is the end diastolic volume (EDV)?
The volume of blood in the ventricles at the end of diastole, approximately 130 mL in a resting adult
What is stroke volume?
The amount of blood pumped by the left ventricle in one contraction
What is cardiac output?
The amount of blood pumped by the heart per minute, calculated as CO = HR X SV
What factors can affect heart rate?
- Fitness Level
- Biological Variability
- Acute Fatigue
- Emotional State
- Music
- Chronic Fatigue/Overtraining
- Sex
- Environment
- Body Position
- Air temperature
- Medication use
What is cardiac hypertrophy?
A thickening of the heart muscle (myocardium)
How does exercise affect stroke volume?
Stroke volume increases after an aerobic training program
What is capillarisation?
The development of the capillary network in a body part due to long-term exercise
What is the relationship between cardiac output and exercise?
Cardiac output increases during exercise due to increased heart rate and stroke volume
What is Boyle’s Law?
The principle stating that pressure and volume have an inverse relationship
What occurs during inhalation?
Increase in lung volume leads to a decrease in lung pressure, causing air to rush in
What is the process of exhalation considered?
A passive process due to elastic recoil of the lung tissue
What are the two types of pleura protecting the lungs?
- Visceral pleura
- Parietal pleura
What is minute ventilation?
The volume of gas inhaled or exhaled from a person’s lungs per minute
How is minute ventilation calculated?
Minute ventilation = Tidal Volume X Respiratory rate
What is the normal tidal volume for a 70 kg person?
Approximately 700 mL
What is hyperpnea?
An increase in ventilation to meet higher oxygen demands during exercise
What are the respiratory centers located in the brainstem?
- Inspiratory center
- Expiratory center
- Pneumotaxic center
- Apneustic center
What are the two categories of metabolism?
- Catabolism
- Anabolism
What is bioenergetics?
The biochemical pathways by which the cell obtains energy
What is metabolism?
The chemical processes that occur within a living organism in order to maintain life.
What are the two main categories of metabolism?
- Catabolism - the breakdown of molecules to obtain energy
- Anabolism - the synthesis of all compounds needed by the cells.
What is bioenergetics?
The biochemical or metabolic pathways by which the cell ultimately obtains energy.
What are the three forms of carbohydrates supplied by foods?
- Starch
- Sugar
- Cellulose (Fiber).
What is the overall reaction for the combustion of glucose?
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy.
What role do proteins play in metabolism?
They are the main tissue builders in the body and help in cell structure, functions, and energy production.
What are essential amino acids?
Amino acids that the human body cannot synthesize and must be obtained from the diet.
List four essential amino acids.
- Lysine
- Tryptophan
- Methionine
- Leucine.
What are the functions of fats in metabolism?
- Concentrated sources of energy
- Form cellular structure
- Absorb fat-soluble vitamins
- Provide reserve storage for energy.
What are essential fatty acids?
- Linoleic acid
- Linolenic acid
- Arachidonic acid.
Do minerals contribute directly to energy needs?
No, they are important as body regulators and play a role in metabolic pathways.
Name three important minerals.
- Phosphorus
- Iron
- Potassium.
What is the role of vitamins in metabolism?
They are essential organic compounds that the human body cannot synthesize and must be included in the diet.
What is adenosine triphosphate (ATP)?
The energy currency of life that stores the energy needed for cellular processes.
What is the phosphagen system?
The fastest way to resynthesize ATP, predominantly used for all-out exercise lasting up to about 10 seconds.
What is anaerobic metabolism?
The metabolic process that occurs without oxygen, primarily through glycolysis.
What is VO2 max?
A measurement of the maximum amount of oxygen your body can absorb and use in one minute.
What happens to VO2 max at high altitudes?
It drops 3 percent with each 1,000 feet of higher altitude.
What is thermoregulation?
The process that allows your body to maintain its core internal temperature.
What is the role of the hypothalamus in thermoregulation?
It controls body temperature and triggers changes to effectors like sweat glands and muscles.
What is the effect of high humidity on thermoregulation?
It reduces the effectiveness of sweating by decreasing the rate of evaporation of moisture from the skin.
What are the physiological responses of the body in hot conditions?
- Sweating for evaporative cooling
- Arteriolar vasodilation to increase blood flow to the skin.
What is vasoconstriction?
The process where arterioles constrict to reroute blood away from the skin and towards the core of the body.
What is shivering?
A muscle response that increases heat production as respiration is an exothermic reaction.
What are ergogenic aids?
Anything that gives you a mental or physical edge while exercising or competing.
What is the effect of amphetamines on the brain?
They increase mental alertness and the ability to stay awake and focused.
What are some adverse effects of amphetamines?
They can negatively affect the brain, central nervous system, and the user’s body.
What is ADHD?
Attention Deficit Hyperactivity Disorder, one of the most common childhood disorders.
What are amphetamines used to treat?
- ADHD
- Narcolepsy
- Chronic fatigue syndrome
How do amphetamines affect neurotransmitters?
They release dopamine and norepinephrine and inhibit reuptake.
What are some effects of amphetamines on performance?
- Increased speed
- Increased power
- Increased endurance
- Increased concentration
What is a main adverse effect of amphetamine use?
Addiction.
List some short-term side effects of amphetamines.
- Cerebral haemorrhage
- Confusion
- Hypertension
- Angina
- Vomiting
- Irritability
- Insomnia
- Dizziness
What are anabolic steroids primarily used for?
To increase muscle mass and strength.
What are some medical uses of anabolic steroids?
- Hypogonadism
- Klinefelter’s syndrome
- Delayed puberty
- Some forms of anemia
- Muscular dystrophy
What effects do anabolic steroids have on performance?
- Increased muscle bulk
- Increased muscle strength
- Faster muscle recovery
What are some common side effects of anabolic steroids?
- Decreased sperm production
- Increased aggression
- Liver disorders
- Acne
- Gynecomastia
What is androstenedione and its potential effect?
A muscle-building supplement that may increase strength.
What is the primary function of beta-blockers?
To block the body’s receptors for adrenaline.
In which sports are beta-blockers commonly used?
Sports requiring a steady hand, such as snooker and archery.
What are potential side effects of beta-blockers?
- Severe blood sugar changes
- Heart failure
- Nausea
- Weakness
What is choline and its role in the body?
A vitamin-like compound essential for normal cell function.
What are some benefits of choline supplementation?
- Reduced fatigue
- Increased vigor before and after practices
What is creatine’s primary benefit for athletes?
Improves strength and helps muscles recover during exercise.
What is human growth hormone (hGH) and its main function?
Produced by the pituitary gland, essential for normal growth and development.
List some medical uses of human growth hormone.
- Dwarfism
- Turner’s syndrome
- Renal insufficiency
- HIV treatment
What are some serious side effects of hGH?
- Gigantism
- Acromegaly
- Cardiac failure
- Diabetes
What are narcotics commonly used for in sports?
To reduce moderate to severe pain.
What are common side effects of narcotics?
- Nausea
- Dizziness
- Addiction
- Mood disturbances
What are some effects of caffeine on performance?
- Improved muscle contractibility
- Increased time to exhaustion
- Enhanced alertness
What are common side effects of caffeine?
- Abdominal pain
- Restlessness
- High blood pressure
What is ephedrine used for in sports?
Temporary relief of shortness of breath and as a central nervous system stimulant.
What are potential side effects of ephedrine?
- Dizziness
- Nausea
- Nervousness
What is cocaine’s primary medical use?
As a topical anesthetic in eye and nose surgery.
What are common side effects of cocaine?
- Myocardial infarction
- Seizures
- Confusion
What are diuretics used for?
To remove excess water from the body.
What are some side effects of cocaine?
- Myocardial infarction (heart attack)
- Cardiac arrhythmia (abnormal rhythm of the heart)
- Cerebral haemorrhage (ruptured blood vessel in the brain)
- Seizures (fits or convulsions)
- Confusion, paranoia & delirium
- Irritability & restlessness
Cocaine use can lead to severe physical and psychological effects, which may require medical attention.
What are diuretics commonly referred to as?
Water pills
Diuretics help the body eliminate excess water.
List three types of diuretics.
- Furosemide
- Chlorothiazide
- Hydrochlorothiazide
Each type of diuretic functions differently to remove excess water from the body.
What medical conditions are diuretics used to treat?
- Hypertension (high blood pressure)
- Oedema (fluid retention, swelling or bloating)
- Cardiac failure
- Liver cirrhosis
Diuretics help manage these conditions by reducing fluid overload.
True or False: Diuretics are used to enhance athletic performance.
False
Diuretics can cause dehydration, negatively affecting performance.
Fill in the blank: Diuretics are often used to lose weight rapidly in sports that require athletes to be within a _______.
set weight limit
This is common in sports like boxing and horse racing.
What is a potential use of diuretics in drug testing?
To dilute the presence of illegal substances and aid their excretion
Athletes may misuse diuretics for this purpose.
What are some side effects of diuretics?
- Dehydration
- Hypotension (low blood pressure)
- Muscle cramps
- Electrolyte disturbances
- Muscle weakness
- Seizures (fits/convulsions)
- Gout
- Fatigue
- Calcium issues
These side effects highlight the risks associated with diuretic use.
