Understanding Muscles: Types, Properties, and Function
Muscles: The Engine of Movement
Muscles are the active part of the locomotor system, soft organs responsible for bodily movement. They are susceptible to stimuli and have the ability to contract and relax.
Muscle Properties
- Excitability: The ability to react to stimuli received from the motor nerve.
- Conductivity: The power of a fiber to transmit electrical impulses via depolarization of the cell membrane.
- Elasticity: The ability of the fiber to recover its original shape.
- Contractility: The ability to
Lipids: Structure, Properties, and Biological Roles
Lipids: An Overview
Lipids are a diverse group of biomolecules characterized by their insolubility in water and solubility in nonpolar solvents. They are primarily composed of carbon, hydrogen, and oxygen, with a lower proportion of oxygen compared to carbohydrates. Some lipids also contain phosphorus, nitrogen, or sulfur.
Classification of Lipids
Lipids can be broadly classified into two categories:
- Saponifiable Lipids: These lipids can be hydrolyzed by alkali (e.g., NaOH) to yield soap. Examples include:
Hormone Pathways: Adrenal Insufficiency, Thyroid, and Diabetes
Corticotropin-Releasing Hormone (CRH) – Adrenocorticotropic Hormone (ACTH) – Cortisol Pathway
Adrenal Insufficiency (Cortisol Hyposecretion)
Because cortisol is needed to permit cardiovascular action of epinephrine, and decreased aldosterone secretion increases sodium/water loss, this can lead to hypotension.
Because cortisol promotes the release of glucose into the bloodstream, this can lead to hypoglycemia.
Primary Adrenal Insufficiency (Addison’s Disease): Loss of adrenal cortisol function due
Understanding the Hip Joint: Anatomy, Function, and Conditions
The hip joint is a ball-and-socket joint that connects the pelvis to the femur (thigh bone). It is one of the largest and most stable joints in the human body, allowing for a wide range of motion while supporting body weight during activities like walking, running, and sitting.
Anatomy of the Hip Joint
Bones:
- Femur (Thigh Bone): The head of the femur forms the ball of the joint.
- Pelvis: The acetabulum, a cup-shaped cavity in the pelvic bone, forms the socket.
Cartilage:
- Articular Cartilage: Covers the
Lower Limb Muscle Anatomy, Joints, and Neuroglia Details
Lower Limb Muscle Anatomy
| Name | Origin | Insertion | Action | Innervation |
|---|---|---|---|---|
| Fibularis Longus (Peroneus Longus) | Proximal lateral fibula, lateral condyle of tibia | Base of first metatarsal, medial cuneiform | Eversion and plantarflexion of foot | Superficial fibular nerve |
| Fibularis Brevis (Peroneus Brevis) | Distal lateral fibula | Base of fifth metatarsal | Eversion and plantarflexion of foot | Superficial fibular nerve |
| Tibialis Anterior | Lateral condyle and proximal tibia, interosseous membrane | Medial cuneiform, base of first metatarsal | Dorsiflexion |
Understanding Muscle Contraction Types, Strength, and Fatigue
Types of Muscle Contraction
Isotonic Contractions
Isotonic contractions occur when muscle fibers contract and change length. They are divided into two types:
Concentric Contractions
A concentric contraction happens when a muscle develops enough tension to overcome resistance, causing it to shorten and move a body part against that resistance.
Eccentric Contractions
An eccentric contraction occurs when the resistance is greater than the tension exerted by the muscle, causing the muscle to lengthen under
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