The Structure and Function of Muscular Tissue Types
Muscular Tissue: Structure and Components
Muscles are made up of highly specialized, thin, and elongated cells called muscle fibers. The muscle fibers contain specialized cytoplasm called sarcoplasm that contains a network of membranes called the sarcoplasmic reticulum. The muscle fibers may be bounded by the cell membrane called the sarcolemma. Each muscle fiber may contain numerous longitudinal fibrils called myofibrils.
Basic Physiological Properties of Muscle Tissue
- Contractility
- Excitability
- Extensibility
- Elasticity
Types
Read MoreSpinal Biomechanics: Structure, Function, and Load Transmission
The spine is a complex mechanical structure that supports the body, protects the spinal cord, and allows controlled mobility. Its biomechanics are governed by the interaction of bones (vertebrae), joints, intervertebral discs, ligaments, and muscles.
1. Structural Features of the Spine
- Vertebrae: 33 in total (7 cervical, 12 thoracic, 5 lumbar, 5 sacral [fused], 4 coccygeal).
- Vertebral bodies bear compressive load.
- Facet (zygapophyseal) joints guide and limit motion.
- Intervertebral Disc (IVD): Acts as
Endocrine Hormones and Musculoskeletal System Function
The Endocrine System: Chemical Messengers
Endocrine glands respond to stimuli by producing hormones transported in the blood throughout the body. Each hormone affects its target cell, which contains specific receptors. Hormones are chemical messengers that activate or stop, accelerate or delay processes within organs. Hormone receptors cause chemical reactions inside the cell, producing a response.
Hypothalamus Function
The Hypothalamus produces nerve signals and hormones, specifically releasing factors
Read MoreMusculoskeletal and Endocrine Pathologies: Arthritis, Spondylitis, and Hormonal Disorders
Joint and Musculoskeletal Disorders
Osteoarthritis (OA)
Degeneration of weight-bearing and finger joints.
Types of Osteoarthritis
- Primary: Associated with weight-bearing stress, obesity, and aging.
- Secondary: Follows trauma or repetitive use.
- Genetics play a role in susceptibility.
Pathological Changes in OA
- Articular cartilage is damaged, leading to the release of enzymes.
- This accelerates cartilage disintegration. Subchondral bone is exposed, leading to the development of cysts, osteophytes, or new bone
Muscle Contraction, Joint Anatomy, and Skeletal Movement
Muscle Contraction and Anatomy Fundamentals
Steps in Skeletal Muscle Contraction
- Calcium ions are released from the sarcoplasmic reticulum.
- Calcium ions bind to troponin.
- Myosin cross-bridges bind to the actin filament.
- The myosin head pivots toward the center of the sarcomere (Power Stroke).
- The myosin head binds an ATP molecule and detaches from actin.
- The free myosin head splits ATP, resetting the head position.
Key Muscle Fiber Structures and Definitions
- Triad (E): Terminal cisternae abutting a T-tubule.
Understanding Muscle and Bone Structure for Movement
The Musculoskeletal System
Muscles are composed of elongated cells called muscle fibers. These organs have the ability to contract and relax. There are several types of muscles:
Smooth Muscle
Characterized by slow, involuntary contractions. Smooth muscle fibers form the walls of various internal organs.
Heart Muscle
This involuntary muscle contracts rapidly. Its fibers are found in the heart (myocardium).
Skeletal Muscle
These muscles enable fast, voluntary movements and are attached to the skeleton. Each
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