Biology Chapter: Bone and Tissue Functions

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Questions and Answers

What is the primary function of osteoblasts in bone tissue?

They lay down new bone tissue. (correct)

They absorb calcium within the bone matrix.

They provide communication between body parts.

They break down old bone tissue.

Which type of tissue primarily forms the outer layer of internal organs, such as in the heart?

Nervous tissue

Connective tissue

Epithelial tissue (correct)

Muscle tissue

What type of bone is characterized by being strong and dense, forming tubular structures filled with marrow?

Cancellous bone

Compact bone (correct)

Fibrous bone

Elastic bone

What type of tissue is responsible for contraction and motion in the body?

Muscle tissue Signup and view all the answers

Which of the following statements best describes Wolf's Law?

Bone remodels itself in response to external stressors. Signup and view all the answers

Which type of connective tissue can be found in joints and serves as a cushioning material?

Cartilage Signup and view all the answers

What component fills the matrix of bone, providing resilience and resistance to compression?

Calcium phosphate Signup and view all the answers

Which structure provides blood supply to the bone and contains progenitor cells for bone repair?

Periosteum Signup and view all the answers

What is the primary function of hyaline cartilage?

It covers the ends of bones to provide protection and lubrication. Signup and view all the answers

What is the primary function of synovial membranes in a joint?

To secrete fluid for lubrication Signup and view all the answers

At what age does the fibula typically finish its growth?

1 year Signup and view all the answers

Which type of ligament is found inside the joint capsule?

Intracapsular ligaments Signup and view all the answers

What type of ligament is characterized by elastic fibers in its matrix?

Elastic ligaments Signup and view all the answers

What is the main purpose of a bursa?

To prevent tendon irritation against bone Signup and view all the answers

Which joint is specifically mentioned as being surrounded by ligaments that restrict movement in certain directions?

Ankle joint Signup and view all the answers

What is a notable characteristic of cartilage?

It is avascular and aneural, limiting self-repair. Signup and view all the answers

Which of the following is NOT a type of muscle mentioned?

Elastic muscle Signup and view all the answers

Which of the following statements about synovial sheathes is true?

They reduce friction for tendons during movement. Signup and view all the answers

Where is fibrocartilage primarily found?

In the knee joints as menisci Signup and view all the answers

Where does the muscle contraction occur primarily?

In the muscle belly where fibers slide Signup and view all the answers

Which bone achieves full growth between the ages of 16 and 18 years?

Phalanges Signup and view all the answers

What type of cartilage is found in the external part of the ear?

Elastic cartilage Signup and view all the answers

What distinguishes skeletal muscle from smooth and cardiac muscle?

It is under conscious control. Signup and view all the answers

What accurately describes the function of the periosteum in relation to synovial membranes?

It helps hold the joint structure together. Signup and view all the answers

What type of muscle fibers are primarily utilized by a marathon runner?

Type 1 - Slow twitch, red (myoglobin) Signup and view all the answers

Which of the following describes the action of the quadriceps muscle during knee extension?

Prime mover (agonist) Signup and view all the answers

During which type of contraction does the muscle shorten while generating force?

Concentric Signup and view all the answers

What happens to muscles that are not actively used over time?

They atrophy Signup and view all the answers

How does reciprocal inhibition work in the context of muscle pairs?

The agonist muscle relaxes while the antagonist contracts Signup and view all the answers

Which skeletal muscle fibers would be most advantageous for a powerlifter?

Type 2x - Fast twitch, white Signup and view all the answers

What is the role of a fixator muscle during movement?

To stabilize an origin point without moving Signup and view all the answers

Which spinal nerves contribute to the femoral nerve?

L2 - L4 Signup and view all the answers

What type of muscle contraction occurs when a muscle generates force while lengthening?

Eccentric Signup and view all the answers

What is a primary function of the skin?

Protection from physical attack Signup and view all the answers

Which layer of skin contains blood vessels and nerves?

Dermis Signup and view all the answers

Which of the following nerves is part of the sacral plexus?

Sciatic Signup and view all the answers

How does the thickness of the epidermis vary across the body?

Thicker on the palms and soles, hairless areas Signup and view all the answers

What is the primary function of lymph nodes in the lymphatic system?

Act as a filter inhabited by phagocytes and antibodies Signup and view all the answers

Which of the following correctly describes the components of the central nervous system (CNS)?

Brain and spinal cord Signup and view all the answers

How are afferent and efferent pathways categorized in the somatic nervous system?

Afferent pathways relay sensory information while efferent pathways send motor commands Signup and view all the answers

Which component of the autonomic nervous system is primarily responsible for increasing the body's alertness and readiness for action?

Sympathetic system Signup and view all the answers

What is the primary role of the neurons in the nervous system?

Transmit electrical impulses for communication Signup and view all the answers

Which of the following regions of the spinal column would house nerves supplying the lower limbs?

Lumbar and sacral regions Signup and view all the answers

What distinguishes the autonomic nervous system from the somatic nervous system?

The autonomic nervous system manages unconscious body functions Signup and view all the answers

Which accurately describes the direction of electrical impulses in a neuron?

They tend to only travel in one direction Signup and view all the answers

Study Notes

Anatomy Lecture 2: Tissues and Structures of the Body

The lecture covered tissues and structures of the lower limbs, radiology, a summary, and a look forward to the next week's topics.
Body organization begins with chemicals, followed by cell components (organelles), cells, tissues, organs, organ systems, and finally, the whole body.
Structures in the body can be composed of one or multiple tissue types.
- Bone is largely connective tissue.
- The heart has epithelial, muscle, and connective tissue, along with nerves.
Tissues are broadly categorized into four types:
- Epithelial: A covering material
- Connective: Connects structures and provides support.
- Muscle: Contracts to cause or control movement.
- Nervous: Enables communication between body parts through electrical impulses.

What Structures Are There in the Body?

Bones
Cartilage
Ligaments
Synovium/Bursa
Muscles
Tendons/Aponeurosis
Joints
Fascia/Adipose tissue
Vascular structures
Neural structures
Skin

Bone

Bone is a living, dynamically changing structure that adapts to stresses. (Wolff's Law)
Functions:
- Protection for other structures
- Framework for other structures
- Levers and pulleys for movement
- Reservoir for calcium and fat
- Formation of blood cells
Structure:
- Cells: Osteocytes (lay down new bone), Osteoclasts ('eat' old bone)
- Matrix: Dense, tough connective tissue lattice containing calcium phosphate; resilient, slightly elastic, resisting compression.
- Supplied by vascular structures and nerves.
- Surrounded by periosteum (two layers: outer fibrous, inner highly vascular 'cambium').

Classifications of Bone

Compact (cortical): Strong, dense, forms tubular bodies, filled with marrow.
Cancellous (spongy): Lattice of bony spicules (trabeculae); helps redistribute stress and absorb shock.

Compact Bone: Structure

Concentric lamellae
Lacunae (spaces)
Canaliculi
Haversian canal
Capillaries
Osteocytes

Cancellous Bone: Structure

Trabeculae
Osteoid
Active osteoblasts
Inactive osteoblasts
Marrow spaces
Osteoblasts
Osteocytes
Osteoclasts

The Tibia

An example of a long bone, featuring
- Proximal epiphysis
- Diaphysis
- Distal epiphysis
- Compact bone
- Spongy bone (marrow)
- Periosteum
- Yellow marrow
- Nutrient artery

Bone Classifications (Based on Shape)

Long bones: Compact (shaft), cancellous (ends), covered with hyaline cartilage.
Example: Femur, Tibia, Metatarsal
Short bones: Primarily cancellous surrounded by a compact shell; cube-shaped. Joint surfaces covered in hyaline cartilage.
- Example: Calcaneus, Talus
Flat bones: Thin inner and outer layer of cortical bone separated by a layer of cancellous bone.
- Example: Skull, Scapula
Irregular bones: Thin shell of compact bone surrounding cancellous bone; odd shapes.
- Example: Vertebrae
Sesamoids: Bones within tendons (e.g., patella).

Bone Marrow

Occupies cavities in long and short bones, and spaces amongst trabeculae in other cancellous bones.
In children, primarily red (hemopoietic); red & white blood cells, platelets.
Gradually replaced by yellow marrow (fatty) after 7 years of age; around 50% of each by adulthood.

Bone Development

Two types:
- Membranous: Bone develops directly from connective tissue membrane.
- Endochondral: Cartilage model is laid down and gradually replaced by bone formation (how limbs form).

Endochondral Bone Development

Stages of cartilage model ossification: The diagram shows stages of ossification, revealing how limbs grow and form.

Ossification Rates (for various bones)

Diagram showing the relative timing of ossification for different bones in the lower limb.

Radiographic view of adult and child knees

X-Ray images of typical knee anatomy for a child and adult

Bones of the Pelvis

Diagram of pelvis bone anatomy (ilium, sacrum, anterior superior/inferior iliac spines, pubis, ischium, iliac crest, sacroiliac joint, obturator foramen, femur).

The Knee

Features of the knee joint components (femur, tibia, fibula, anterior/posterior cruciate ligaments, medial/lateral collateral ligaments, medial/lateral meniscus).

Rear Foot & Ankle

Diagram of ankle joint components (tibia, fibula, talus, calcaneus, cuboid, navicular, cuneiforms, metatarsals, interosseous ligament, medial/lateral ligament, talocalcaneal ligament).

Cartilage

Connective tissue made of collagen embedded in a gel-like matrix.
- Hyaline: Important in joint formation, protecting bone surfaces.
- Fibrocartilage: Tough, found in weight-bearing joints (knee menisci)
- Elastic: Springy, found in the ears.

Ligaments

Bands of connective tissue connecting two bones.
- Often allow motion in one direction but restrict it in others.
- Types:
  - Inelastic: Dense bundles of collagen; e.g., ankle & knee.
  - Elastic: Elastic fibers; e.g., plantar calcaneonavicular ligament.
- Ligaments within the joint capsule are intracapsular; those outside are extracapsular.

Synovial Membranes/Sheaths and Bursae

Fluid-filled sacs that reduce friction and protect tendons and joints.
- Synovial membranes: inner lining of joints; secretion helps lubricate.
- Synovial sheathes: Similar to synovial membranes, but they surround tendons.
- Bursae: Sacs situated under tendons to prevent friction from bony lumps

Muscles

Muscles enable body movement.
- Types: Cardiac, smooth, skeletal.
- Skeletal muscle: Under conscious brain control, composed of striated fibers.
  - They work by contracting, in various shapes
    - Rhomboid
    - Quadrilateral
    - Strap
    - Strap with tendinous intersections
    - Fusiform
    - Two bellies
    - Two headed
    - Triangular
    - Unipennate
    - Bipennate
    - Multipennate
  - Have points of origin (attachment that doesn't move much) and insertion (attached to another part by a tendon).
  - Types of contraction (dynamic - eccentric/concentric; static - isometric).
  - Jobs performed by skeletal muscles
    - Prime mover (Agonist): Causes a movement.
    - Antagonist: Works against a prime mover.
    - Fixator (stabilizer): Holds a body part stable during a movement, while the other muscles perform the desired movement.
    - Synergist: Assists the prime mover.
Muscle Structure
Includes tendons and aponeuroses (fibrous tissue, connecting muscle to bone)

Skeletal Muscle Types

Type 1: Slow twitch, red (myoglobin) — Marathon runner.
Type 2a: Quite fast twitch, white — 800-meter runner.
Type 2x (formerly 2b): Fast twitch, white — 100-meter runner, powerlifter.

Muscles & Stress

Muscles and soft tissues grow stronger with use (Davis' Law).

Tendon/Aponeurosis

Tendons: Long inelastic cords of connective tissue attaching muscles to bones.
- Tendons cross over joints and may cause motion some distance from the muscle, even going around corners.
Aponeurosis: Thin, wide sheets of connective tissue that also attach muscles to bones (e.g., ventral abdominal aponeurosis).

Joints

Junctions where two or more bones meet.
Types:
- Fibrous: Negligible or no movement(skull sutures).
- Cartilaginous: Small amount of movement (symphysis pubis).
- Synovial: Large range of motion (hip, knee, elbow).

Fibrous Joints

Bone margins interlock like jigsaw pieces; inherently rigid and stable.
Sharpey's fibers strongly bind the bones.

Cartilaginous Joints

Bones are united by a plate of fibrous cartilage, with a thin layer of hyaline cartilage on the ends of the bones.

Synovial Joints

Highly moveable; trade-off between stability and maneuverability (depends on shape, ligament strength, and muscle control).

Joint Shapes

Types of synovial joints (hinge, ball-and-socket, pivot, plane, saddle, condyloid, ellipsoid).

Fascia

Membranes surrounding deep structures in the body.
- Superficial: Surrounds everything under the skin.
- Deep: Divides deep structures into compartments (e.g., thigh compartments).

Fascial Adaptations

Retinacula (thickening of fascia) holds tendons, blood vessels, and nerves in place.
Tracts (e.g., iliotibial tract) provide stability.

Cardiovascular System

Heart and blood vessels pump blood around the body and back to the heart.
- Pulmonary and Systemic systems.
- Heart: Muscular bag with 4 chambers — contracts to push blood to other body parts.
- Other vessels: Takes blood to and from the heart (arteries, arterioles, metarterioles, pre-capillary sphincters, capillaries, venules, veins)

What Does the CV System Do?

Exchange of gases (oxygen in, carbon dioxide out).
Delivers nutrients and hormones.
Removes waste products.
Protection (clotting, leukocytes).
Temperature regulation.
Homeostasis.

Arteries

Muscular and elastic walls deliver blood from the heart to other places.
Aid in heart pumping
High pressure.

Veins

Less muscular and elastic than arteries.
Deliver blood back to the heart from everywhere else.
Lower pressure system.
One-way valves prevent backflow.

Capillaries

Tiny vessels with walls one cell thick.
Leaky—diffusion of oxygen, nutrients, carbon dioxide, and waste products.

Anastomosis

Joining of blood vessels, allowing blood to pass from one vessel to another (useful if one vessel is blocked).

Lymphatics

Parallel system with veins, carrying fluid and proteins away from tissues to blood.
Drain into large veins.
Lymph nodes act as filters, containing phagocytes and antibodies.

The Nervous System

Body's communication system (processes information and controls actions).
Types of Nervous Systems
- Central nervous system (CNS): Brain and spinal cord
  - Integration and control center for body functions.
- Peripheral nerves system (PNS): Cranial and spinal nerves
  - Connects the CNS to the rest of the body; communication pathway for impulses from the brain, and back to the brain, from the rest of the body
- Somatic Nervous System: Voluntary actions
- Automatic Nervous System: Actions not under conscious control (sympathetic & parasympathetic).

Somatic: Afferent & Efferent

Sensory (afferent) impulses from body to the brain.
Pain, temperature, vibration, pressure, muscle and tendon tension, and joint position.
Motor (efferent) impulses from the brain to the muscles for body movements

Autonomic

Functions not under conscious control.
- Sympathetic: "revs up" body for action.
- Parasympathetic: "slows down" body for rest, recovery. (balance eaching).

Cranial Nerves

Nerves that originate in the brain; involved in various functions including sensory perception and motor control (diagram of each).

Spinal Nerves

Originate from spinal cord—supply specific body parts (diagram).

Lumbar & Sacral Plexi

Nerve networks from several spinal nerves that distribute to the lower limbs.

Main Nerves of the Lower Limbs

Femoral (L2-L4)
Obturator (L2-L4)
Sciatic (L4-S3)

Skin

Largest organ, covering 1.5 to 2 square meters and weighing about 16% of body weight.
- Protection
- Temperature control
- Receptors
- Vitamin D synthesis
- Communication

Skin: Structure

Layers:
- Epidermis (outer surface, stratified, thick on palms & soles).
- Dermis (deeper, containing blood vessels, nerves, hair roots, and glands).
- Subcutaneous tissue (fat and connective tissue).
Diagram of skin structure showing layers, hair follicles, sweat glands, oil glands.

Summary

Overview of the various anatomical concepts and their connections.

Next Week

Instructions to revise notes and textbook material; prepare for osteology of the lower limb, focusing on anterior thigh compartment and surface anatomy, as well as time and location.

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Description

Test your knowledge on the functions and types of bone and connective tissues with this quiz. Explore key concepts such as osteoblast activity, Wolf's Law, and the roles of various tissues in the human body. Challenge yourself and see how well you understand these fundamental biological principles.