Human Anatomy and Physiology: Muscles, Respiration, Circulation, and Chemical Composition

Muscle Contractility and Mechanism

What is the unit of muscle contractility and how would you explain briefly the mechanism of muscle contraction?

The basic unit of muscle contraction is the sarcomere. It is composed of protein filaments: actin and myosin. Actin filaments are fixed in a longitudinal direction, while myosin filaments are free. During contraction, the length of the actin and myosin filaments does not change. Instead, the sarcomere shortens due to the sliding of the actin filaments over the myosin filaments towards the center of the sarcomere. This sliding is driven by the interaction between actin and myosin, which is regulated by calcium ions. Calcium is essential for muscle contraction.

Respiratory Physiology

Explain VO2 max and anaerobic threshold.

VO2 max is the maximum rate of oxygen consumption that a person can achieve during exercise. It is a measure of cardiorespiratory fitness. At some point during strenuous exercise, we reach a maximum value of VO2 that cannot be exceeded. This value can be expressed as the amount of oxygen consumed per minute.

The anaerobic threshold is the point at which the body begins to produce lactic acid. This occurs after a certain percentage of VO2 max is reached. Lactic acid accumulation is a sign that the body is not able to supply enough oxygen to meet the demands of exercise.

Circulatory System

Difference between veins, arteries, and capillaries.

Arteries carry oxygenated blood away from the heart. Veins carry deoxygenated blood back to the heart. Capillaries are the smallest blood vessels and serve as the connection between the terminal branches of arteries and veins. They are responsible for the exchange of gases, nutrients, and waste products between the blood and the tissues.

Chemical Composition of the Human Body

Chemical analysis, definition.

The human body is composed of approximately 60% water and 40% dry matter. The dry matter includes 18% protein, 15% lipids, 1% carbohydrates, and 6% minerals. The main chemical elements in the human body are carbon, oxygen, and hydrogen, with some nitrogen and very small amounts of other elements.

Musculoskeletal System

Longest muscle in the human body

The longest muscle in the human body is the sartorius.

Anterior cruciate ligament

The anterior cruciate ligament prevents the knee from moving forward over the thigh.

Quadriceps

: rectus muscle, origin: iliac spine anteroinferior.musculo vastoexterno, origin: linea aspera of crural femur.musculo, origin: anterior part of the shaft vastus femural.musculo: Origin: linea aspera of femur.Inserccion: some fibers d dl vastus rotula.Los are inserted into the remaining muscles attach through tendon.a turn, the patella is attached to the tibial tuberosity by patellar ligament. PIE: mov.2jes, the flexo-extension called mov.se and supination-pronation.

PIE: the flex-ext. are between the (talus) and (tibia and fibula). supination and pronation in the ankle ligaments astragalo.Los originate from the tibial and fibular malleolus and extending downward direction of the articulating bones ligament tobillo.El Internal inserts into the calcaneus, talus and navicular, is known as deltoideo.El ligament ligament is composed of 3 ligaments distintos.Todos peroneal malleolus start from one of them is inserted into the talus (anterior talofibular), another in calcaneus (peroneal-calcaneus) and third in the back of the talus (peroneal-astagalino later). Flexor most important is the triceps surae.Extenders most important between the tibia and fibula. Leg: triceps surae three parts: twins with their 2 heads of origin and soleus, and the 3 parts together form the achilles tendon d, k is inserted inthe calcaneus