A

Week 8 Bone Features, Order Anura

Welcome & Introduction

  • Instructor: Nirosha Murugan, PhD

    • Assistant Professor of Biology at Algoma University.

    • Focus areas: regenerative medicine, cancer biology, neuroscience.

    • Notable work: Regrowing a functional limb in frogs using a five-drug cocktail.

    • Key insight: Potential for dormant regenerative capabilities in frogs and other animals.

Lab Exam 2 Overview

Point Breakdown

  • Total Points: 43

  • Graded out of: 40 points

  • Bones Section: 33-36 points

    • 1 point for proper names (no colloquial terms like collarbone, cheekbone).

    • 0.5 points for Anterior vs. Posterior, Right vs. Left, and Bone features.

    • Possible definitions per checklist.

  • Frog Section: 7-10 points

    • External/internal anatomy and muscles (1-2 points).

    • Background info from PowerPoint (PPT).

    • Prepared microscope slides are important; major tissue types for Cephalochordata/amphioxus.

  • Questions based strictly on checklists and PowerPoints.

Lab Exam 2 Details

  • Location: IO306 (lab)

  • Date: Tuesday, March 11th

  • Schedule:

    • Last Names A-K: 11:20 AM (Doors open), 11:30 AM (Exam starts)

    • Last Names L-W: 12:20 PM (Doors open), 12:30 PM (Exam starts)

  • Exam Duration: 30 minutes (approx. 30 seconds per question).

  • Policy: Do not knock on the door once closed; wait for it to reopen.

  • What to Bring: Pencil or Pen (blue/black ink only).

Lab Safety Guidelines

  • Eye Protection: Mandatory.

  • Attire: Closed-toe shoes, long pants.

  • Hygiene: Sanitize work areas and dissection kits upon entering/leaving.

  • Allergens: Be aware of latex.

Biological Classification Overview

Basic Concepts

  • Organization Levels:

    • Parazoa, Eumetazoa

    • Symmetry types: Radial, Bilateral

  • Key Terms:

    • Choanoflagellates, Radiata, Gastrulation

    • Body Cavity: Acoelomates, Pseudocoelomates, Coelomates.

    • Development types: Protostomia, Deuterostomia.

Characteristics of Chordates

  • General Features:

    • Found in aquatic and terrestrial environments.

    • Distinct head and trunk supported by cartilage or vertebrate structures in adults.

    • Features: Notochord, well-developed brain, sensory organs, dorsal nerve cord, closed circulatory system.

  • Examples: Reptiles, amphibians, birds, mammals.

Bone Anatomy

Types of Bone Markings

  • Non-articulation Markings (for muscle attachment):

    • Trochanter: Large, blunt projection (femur).

    • Tuberosity: Large rounded projection (tibia, ulna).

    • Tubercle: Small rounded projection (humerus, radius).

    • Crest: Narrow projection forming a ridge (ilium, tibia).

    • Spine: Slender bone extension (vertebrae).

    • Process: Sharp, slender extension (radius).

  • Joint Formation Markings:

    • Head: Rounded region at the proximal end of a bone (femur).

    • Facet: Shallow, smooth surface (ribs, vertebrae).

    • Condyle: Round knob (mandible, femur).

Depressions/Openings

  • Meatus: Canal-like passage (temporal).

  • Sinus: Air-filled cavity within a bone (frontal, sphenoid).

  • Fossa: Shallow bone depression (temporal, scapula).

  • Sulcus: Furrow along a bone (humerus).

  • Fissure: Narrow opening for blood vessels or nerves (orbital).

  • Foramen: Round opening for vessels/nerves (occipital).

Amphibia Class Overview

Characteristics of Amphibians

  • Aquatic and terrestrial organisms.

  • Distinct features:

    • Protruding eyes, cleft tongue.

    • Maxillary and vomerine teeth, semi-permeable skin.

    • Undergo metamorphosis; exhibit sexual dimorphism with males having vocal sacs.

Internal Anatomy of Frogs

Circulatory and Digestive Systems

  • Heart: 3-chambered.

  • Lungs and Digestive System:

    • Function: Processes food for absorption into the bloodstream.

    • Organs included: Stomach, intestines, gall bladder, spleen.

Urogenital System

  • Function: Waste extraction/processing from blood & reproduction.

  • Organs included: Kidneys, adrenal glands, testes (males), ovaries (females), cloaca.

Muscle Tissue

Functions

  • Produces body movements.

  • Stabilizes body positions.

  • Stores/moves substances within the body, contributes to metabolism.

  • Generates heat through muscle activity.

Properties

  • Electrical Excitability: Action potentials.

  • Contractility: Ability to shorten forcefully.

  • Extensibility: Ability to stretch.

  • Elasticity: Ability to return to original shape.

Types of Muscle Tissue

  1. Skeletal Muscle:

    • Striated, tubular, voluntary, multi-nucleated, usually attached to skeleton.

  2. Cardiac Muscle:

    • Striated, branched, involuntary, present only in heart walls.

  3. Smooth Muscle:

    • Non-striated, spindle-shaped, involuntary, found in internal organs.

Histology of Skeletal Muscle

  • Components:

    • Nuclei, striations, endomysium.

  • Structures:

    • Longitudinal section (l.s.), cross-section (c.s.).

Skeletal Muscle Hierarchy

  • Muscle fiber (cell) → Endomysium → Fascicle → Perimysium → Epimysium → Tendon → Motor neuron → Blood vessels.

Sarcomeres

Key Points

  • Basic contractile unit of myocyte.

  • Composed of thick filaments (myosin) and thin filaments (actin, tropomyosin, troponin).

Frog Muscle Identification

  • Ventral Muscles: Rectus abdominis, Pectoralis, Sartorius, Adductor magnus, Triceps femoris, Gastrocnemius.

  • Dorsal Muscles: Adductor magnus (cut), Gracilis major, Triceps femoris, Semimembranosus, Latisimus dorsi.

To Do List for Students

  • Dissect preserved Frog specimen.

  • Review external and internal anatomy, bone identification, and muscle features.

  • Study prepared slides of skeletal muscle.

  • Familiarize with striated muscle structures.