Assignment 1 preparation

Introduction to Anatomy

• Anatomy: From ancient Greek, meaning "dissection" or "to cut." It is the study of the structure and relationships of body parts.

• Anatomical Language: Essential for medicine, uses specialized vocabulary often derived from Latin and Greek for clear descriptions.

• Anatomical Position: A conventional reference for all descriptions:

  • Standing erect, facing forward.

  • Upper limbs by sides, palms facing forward.

  • Lower limbs together, toes facing front.

• Anatomical Planes: Imaginary reference planes:

  • Sagittal Plane: Divides the body longitudinally into left and right parts.

  • Frontal (Coronal) Plane: Divides the body vertically into anterior (front) and posterior (back) parts.

  • Transverse (Horizontal) Plane: Divides the body horizontally into superior (upper) and inferior (lower) parts.

Anatomical Terminology & Movements

• Directional Terms (Relative to Body/Reference Point):

  • Superior (cranial): Towards the head end or upper part; above.

  • Inferior (caudal): Away from the head end or towards the lower part; below.

  • Anterior (ventral): Towards or at the front; in front of.

  • Posterior (dorsal): Towards or at the back; behind.

  • Medial: Towards or at the midline; on the inner side of.

  • Lateral: Away from the midline; on the outer side of.

  • Intermediate: Between a more medial and a more lateral structure.

• Directional Terms (Relative to Origin/Attachment):

  • Proximal: Closer to the origin of a body part or limb attachment.

  • Distal: Farther from the origin of a body part or limb attachment.

• Directional Terms (Relative to Body Surface):

  • Superficial (external): Towards or at the body surface.

  • Deep (internal): Away from the body surface; more internal.

• Movement Terms (Angle Changes):

  • Flexion: Decreasing the angle between two bones, typically in the sagittal plane.

  • Extension: Increasing the angle between two bones, typically in the sagittal plane.

• Movement Terms (Limb Movement):

  • Abduction: Moving a limb away from the body midline in the frontal plane.

  • Adduction: Moving a limb toward the body midline in the frontal plane.

  • Circumduction: Moving a limb or finger to describe a cone in space.

• Movement Terms (Rotation):

  • Rotation: Turning a bone around its longitudinal axis.

  • Medial Rotation: Rotating toward the median plane.

  • Lateral Rotation: Rotating away from the median plane.

• Other Concepts:

  • Antagonist: Opposes a movement or principle (e.g., muscle holding against gravity).

  • Eccentric Contraction: Muscle working while getting longer (e.g., slowly lowering a weight).

Body Tissues

Epithelial Tissue

• Origin: "Epi" (Greek) means "upon" or "on top of."

• Location: Covers other tissues; one surface attached to underlying tissues, other exposed to environment.

• Characteristics:

  • Polarity: Has an apical (top, exposed) and basal (attached to connective tissue) surface.

  • Specialized cell contacts.

  • One free surface.

  • Supported by connective tissue.

  • Avascular (no blood supply) but has nerve supply.

  • Capacity to regenerate.

• Examples: Skin, linings of hollow structures (intestines, bladder, uterus, vagina, urethra).

Nervous Tissue

• Function: Main component of the nervous system, conducts information.

• Cell Types:

  • Neurons: Specialized cells that generate and conduct nerve impulses.

  • Glial Cells (Neuroglia): "Glia" means glue. Support and protect neurons. Ratio to neurons is 1:1.

Muscle Tissue

• Function: Responsible for movement.

• Characteristics:

  • Highly vascularized (needs oxygen/nutrients, removes waste).

  • Contains myofilaments for contraction.

  • Connective tissues (tendons, fascia) have small blood supply (appear white).

  • Tightly packed cells.

• Types & Innervation:

  • Skeletal Muscle: Voluntary control.

  • Smooth Muscle: Involuntary control.

  • Cardiac Muscle: Involuntary control, found only in the heart.

• Cardiac Muscle Specifics:

  • Pumps blood throughout the body.

  • Attached to a fibrous skeleton of the heart.

  • Cells strongly attached by intercalated discs.

Connective Tissue

• Bone:

  • Withstands compressive and tensile forces (stronger than cartilage, less flexible).

  • Cells:

  • Osteoblasts: Bone-forming cells; lay down extracellular matrix (collagen) and ground substance (calcium, phosphate).

  • Osteocytes: Mature bone cells (osteoblasts trapped within matrix).

  • Properties: Good blood supply and innervation; continuously remodeled; heals well.

• Blood: Classified as a connective tissue.

Body Systems (General Overview)

• Definition: A group of organs and tissues working together for specific, survival-essential functions.

• Number: There are 11 body systems.

• Interactions: All systems interact (e.g., urinary system requires cardiovascular system).

• Tissue Composition: Each body system contains all four main tissue types (connective, muscular, nervous, epithelial).

Integumentary System

• Meaning: Latin "integumentum" means "covering" or "shield."

• Functions: Guards internal environment from external, temperature regulation, sensation.

• Components: Skin (epidermis, dermis), appendages (hairs, nails, sweat glands, sebaceous glands).

• Skin Structure:

  • Epidermis: Outermost layer, made of epithelial tissue, thickness varies (0.05mm - 1.5mm).

  • Dermis: Layer just below the epidermis.

• Skin Color: Differences primarily due to melanin amount and distribution.

Skeletal System

• Components: Bones, cartilage, ligaments (dense, fibrous connective tissue stabilizing joints).

• Functions:

  • Provides a frame for body support.

  • Supports soft organs.

  • Skeletal muscles anchor for leverage in movement.

  • Protects softer tissues (e.g., skull protects brain).

  • Stores important minerals (calcium, phosphate).

Muscular System

• Primary Function: Movement.

• Cardiac Muscle: Located only in the heart; pumps blood; cells connected by intercalated discs.

Nervous System

• Parasympathetic Nervous System: Responsible for "rest and digest" functions (e.g., decreased heart rate, stimulated digestion).

Endocrine System

• Function: One of two major control systems (the other is the nervous system, which is faster).

• Control Mechanism: Via hormones traveling through the bloodstream.

• Speed/Duration: Slower than the nervous system, but effects are longer-lasting.

• Organs: Includes pituitary gland (in brain) and other glands throughout the body.

Cardiovascular System

• Heart Valve Auscultation Points:

  • Pulmonary Valve: Inferior to the second rib or between 2nd and 3rd rib, just to the left of the sternum.

  • Mitral (Bicuspid) Valve: Midclavicular line, just inferior to the 5th rib.

  • Tricuspid Valve: Palpate the sternum inferior to the 5th rib.

Lymphatic System

• Primary Function: Returns approximately 3 liters of fluid daily to the bloodstream, maintaining blood pressure.

• Secondary Function: Filters out foreign bodies (e.g., bacteria) before fluid returns to the bloodstream.

• Structures:

  • Lymphatic Capillaries: Blind-ended vessels that collect excess extracellular fluid.

  • Lymph Nodes: Filtering areas where lymphatic fluid is cleaned of pathogens.

Respiratory System

• Function: Respiration (gas exchange).

• External Respiration: Gas exchange between alveoli and bloodstream in the lungs.

• Internal Respiration: Gas exchange between blood and cells.

• Ventilation: The flow of air into and out of the lungs (no gas exchange in these passages).

• Air Pathway: Nose/nasal cavity \rightarrow Mouth (optional) \rightarrow Pharynx (both food and air) \rightarrow Larynx \rightarrow Trachea \rightarrow Primary Bronchi (left/right lungs) \rightarrow Divides into smaller bronchi \rightarrow Alveolar sacs (where gas exchange occurs).

Digestive System

• Components: Alimentary canal (tubing for food) and accessory organs (aid digestion).

• Alimentary Canal Pathway: Mouth \rightarrow Pharynx \rightarrow Oesophagus \rightarrow Stomach \rightarrow Small Intestine \rightarrow Large Intestine \rightarrow Anus.

• Nature: Both ends open to the external environment; considered outside the body.

Urinary System

• Primary Function: Filters blood to remove waste products (requires proper cardiovascular system function).

• Structures & Locations:

  • Kidneys: Right kidney is often pushed down by the liver.

  • Ureters: Leave medial aspect of kidneys, run inferiorly/lateral to vertebrae, enter pelvis, drain posteriorly into bladder.

  • Bladder: Lies posterior to the pubic bone, inside the pelvis.

  • Urethra: Tube carrying urine from bladder to external environment. Length varies by sex (shorter in individuals with a vagina, increasing infection risk to bladder).

Reproductive System (Male Focus in notes)

• Sperm Pathway: Epididymis \rightarrow Ductus Deferens (vas deferens, runs posterior to the bladder) \rightarrow Urethra (sperm and urine exit via the penis).

• Prostate Gland: Contributes fluid to sperm, surrounds the urethra. An enlarged prostate can compress the urethra, causing urination difficulty.