Anatomy of Pelvis, Lower Limb Bones, and Muscles
Pelvic Girdle Anatomy
Bones of the Pelvic Girdle
The pelvic girdle bones are the innominate (or iliac) bones, the sacrum, and the coccyx.
Pelvic Girdle Joints
The joint connecting the two pelvic bones is called the symphysis pubis.
Features of the Ilium
The iliac or innominate bone is formed from the fusion of three bones: the ilium, pubis, and ischium.
Iliac Crest Function
The iliac crest serves as an insertion point for the abdominal muscles.
Lower Limb Bone Anatomy
The Femur
Femur Articulations
The femoral
Read MoreUnderstanding Amino Acids and Protein Structure
Properties of Amino Acids
Stereoisomerism occurs because the alpha carbon is asymmetric. Stereoisomers are considered two different optical activities. Amino acids can be isomers L, while D isomers are also present. These isomers can influence antibiotic-bacterial properties. The existence of polar groups in amino acids enables hydrogen bonding, which affects their melting points, boiling temperatures, and solubility.
Peptide Bonds
A peptide bond is the union between the carboxyl group of one amino
Read MoreHuman Anatomy: Joints, Muscles, and Nerve Function
Understanding Joint Structures and Types
Fibrous Joints: Immovable Connections
These are typically immovable joints where bones are united by dense fibrous connective tissue.
Sutures: Skull’s Interlocking Joints
Ridged, interlocking joints found primarily in the skull.
Syndesmoses: Ligament-Connected Bones
Bones are connected by ligaments. Fiber length varies, so movement distance also varies. For example, the connection between the fibula and tibia involves short fibers, while the connection between
Scapula Anatomy and Function
The scapulae, commonly referred to as the shoulder blades, are two large, triangular bones located on the upper back. They play a crucial role in the mobility and stability of the shoulder joint.
Anatomical Location
- The scapulae are situated on the posterior (back) side of the rib cage, one on each side of the body. They articulate with the clavicle (collarbone) at the acromioclavicular joint and with the humerus (upper arm bone) at the glenohumeral joint.
Shape and Structure
- Triangular Shape: The scapula
Understanding Muscle Types and Contraction Mechanisms
Striated Muscle Characteristics
Light microscopy reveals that both skeletal and cardiac muscle fibers exhibit alternating light and dark bands, or striations. These bands change relative size during contraction. Striated muscle fibers contract rapidly but fatigue easily; they require periods of rest before contracting again.
Cardiac Muscle Details
Located in the walls of the heart, cardiac muscle is involuntary, controlled by the autonomic nervous system. Its fibers are joined end-to-end, branching
Read MoreHuman Body Systems: Muscles, Skeleton, Anatomy, Circulation
Human Body Systems Fundamentals
Muscular System Basics
Muscle Types
- Skeletal: Striated, voluntary, multinucleated.
- Smooth: Non-striated, involuntary, single-nucleated.
- Cardiac: Striated, involuntary, single/binucleated.
Muscle Properties
- Contractility: Shortens with stimulation.
- Extensibility: Stretches without damage.
- Elasticity: Returns to original shape.
Muscle Fiber Types
- Slow-Twitch (Type I): Endurance, aerobic.
- Fast-Twitch (Type II): Quick, anaerobic (Type IIa, Type IIb).
Muscle Contraction Mechanism
Contraction:
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