A&P exam two (copy)

Connective Tissue

Connective tissue is a type of tissue in your body that serves a lot of important purposes. Think of it like the glue that holds everything together! Here are some key points about connective tissue:

• What it Does: Connective tissue helps support and connect different parts of your body, like your muscles, bones, and organs.

• Where it Begins: All connective tissues start from special cells called mesenchyme.

• Blood Supply: Different types of connective tissue have different amounts of blood vessels. Some have lots, while others don’t have many at all.

• Parts of Connective Tissue: It’s made of two main parts:

  • Ground Substance: This is a jelly-like material that fills the space between the cells.

  • Fibers: There are three types of fibers:

    • Collagen: These are super strong fibers that help keep everything in place.

    • Elastic: These are stretchy fibers that allow tissues to go back to their original shape, similar to a rubber band.

    • Reticular: These fibers are like a supportive net that helps hold other tissues in place.

• Types of Cells: The main cells in connective tissues are called 'blasts' (which build new tissue) and 'cytes' (which are mature tissue cells).

So, connective tissue is essential for holding your body together and helping it function properly!

Connective tissue is like the glue of your body. It holds everything together and helps support other tissues and organs. Here are some common things about connective tissue:

1. Starts from the Same Place: All connective tissues come from a special kind of cell called mesenchyme.

2. Different Blood Supply: Some types of connective tissue have more blood vessels than others.

3. Made of Two Main Parts: Connective tissue is made up of:

   • Ground Substance: This is like a (jelly-like material) that fills the space between cells.

   • Fibers: There are three kinds of fibers:

     • Collagen: These fibers are super strong and help tissues hold together.

     • Elastic: These fibers can stretch and go back to their original shape, like a rubber band.

     • Reticular: These fibers are like a supportive net that helps hold things in place.

4. Cells: The main cells in connective tissues are called 'blasts' (which build new tissue) and 'cytes' (which are mature tissue cells).

Key Characteristics of Connective Tissue

1. Origin: All types of connective tissue come from a special type of cell called mesenchyme.

2. Blood Supply (Vascularity): The amount of blood vessels varies among different types of connective tissue.

3. Extracellular Matrix: This is the material outside of the cells that provides support and structure to the tissue.

4. Ground Substance: A jelly-like substance filling the space between the cells, part of the extracellular matrix.

5. Fibers:

   • Collagen Fibers: Strong fibers that are made of collagen, providing high tensile strength to the tissues.

   • Elastic Fibers: Made from elastin; these fibers let tissues stretch and then return to their original shape, like a rubber band.

   • Reticular Fibers: Branching fibers made from collagen that create a supportive network around small blood vessels and organs.

6. Cells:

   • Blasts: These are cells that build new tissue.

   • Cytes: These are mature tissue cells that maintain the tissue.

3. For each type of connective tissue, know the functions, locations, type of cells, fibers, matrix

composition, and any unique modifications

Loose Connective Tissue

1. Areolar Connective Tissue

Functions:

• Provides support and binds different tissues together.

• Plays a role in energy storage, especially in adipose tissue.

• Cushions organs and minimizes friction between them.

Locations: Situated beneath epithelial tissues and surrounding various organs.

Type of Cells: Contains fibroblasts, mast cells, macrophages, and some white blood cells.

Fibers: Composed of collagen, elastic, and reticular fibers.

Matrix: Features a gel-like ground substance with loosely arranged fibers.

2. Adipose Tissue

Functions:Acts as an energy reservoir by storing fat. Provides insulation and cushioning for organs.

Locations: Distributed throughout the body, particularly beneath the skin and surrounding internal organs.

Type of Cells: Predominantly made up of adipocytes (fat cells).

Fibers: Contains minimal fibers, primarily collagen surrounding the adipocytes.

Matrix: Nearly devoid of matrix; mainly filled with adipocytes.

3. Reticular Connective Tissue

Functions: Provides structural support and forms a framework for organs.

Locations: Found primarily in lymphoid organs, such as the spleen, lymph nodes, and bone marrow.

Type of Cells: Composed of reticular cells that synthesize reticular fibers.

Fibers: Mainly consists of reticular fibers that create a supportive netting structure.

Matrix: Contains a gelatinous ground substance that supports both reticular fibers and cells.

Dense Connective Tissue

1. Dense Regular Connective Tissue

• Functions: Provides strong attachment between structures, with great tensile strength in one direction.

• Locations: Tendons (connecting muscles to bones) and ligaments (connecting bones to other bones).

• Type of Cells: Predominantly fibroblasts.

• Fibers: Mostly collagen fibers, regularly arranged for strength.

• Matrix: Thick and densely packed ground substance with minimal space between fibers.

2. Dense Irregular Connective Tissue

• Functions: Provides strength and support in multiple directions.

• Locations: Dermis of the skin, fibrous capsules of organs and joints.

• Type of Cells: Fibroblasts and macrophages.

• Fibers: Collagen fibers are irregularly arranged.

• Matrix: Dense with a lot of collagen that allows for multidirectional strength.

3. Elastic Connective Tissue

• Functions: Allows tissues to stretch and recoil.

• Locations: Found in large arteries (like the aorta), certain ligaments, and the respiratory system.

• Type of Cells: Fibroblasts.

• Fibers: Contains elastic fibers that give it stretchability.

• Matrix: Mostly elastic fibers with some collagen.

Cartilage

1. Hyaline Cartilage

• Functions: Provides support and flexibility, reduces friction at joints.

• Locations: Articular surfaces of joints, costal cartilage in ribs, and in the nose.

• Type of Cells: Chondrocytes located in lacunae.

• Fibers: Fine collagen fibers not visible under a microscope.

• Matrix: Gel-like, rich in proteoglycans.

2. Elastic Cartilage

• Functions: Maintains shape while allowing flexibility.

• Locations: External ear and epiglottis.

• Type of Cells: Chondrocytes.

• Fibers: Abundant elastic fibers.

• Matrix: Similar to hyaline cartilage but contains more elastin.

3. Fibrocartilage

• Functions: Provides tough support and absorbs compressive shock.

• Locations: Intervertebral discs, pubic symphysis, and menisci of the knee.

• Type of Cells: Chondrocytes and fibroblasts.

• Fibers: Thick collagen fibers arranged in parallel.

• Matrix: Dense matrix that can withstand tension.

Bone

• Functions: Supports and protects organs, stores calcium, and produces blood cells.

• Locations: Throughout the skeleton in the body.

• Type of Cells: Osteocytes, osteoblasts, and osteoclasts.

• Fibers: Collagen fibers are present, providing strength.

• Matrix: Hard, calcified matrix rich in minerals (mainly calcium phosphate).

Blood

• Functions: Transports nutrients, gases, hormones, and waste products throughout the body.

• Locations: Circulates within blood vessels and the heart.

• Type of Cells: Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets.

• Fibers: Plasma (liquid matrix) does not contain fibers under normal conditions. Fibrin fibers can form during clotting.

• Matrix: Liquid matrix called plasma, which is composed of water, electrolytes, proteins, and other solutes.

Integumentary System Overview

1. Basic Characteristics of the Three Regions of the Skin:

   • Epidermis: This is the outermost layer of skin. It contains living and dead cells, with the outermost part being made up of dead cells that help protect against the outside world.

   • Dermis: Located beneath the epidermis, this layer contains blood vessels, nerves, hair follicles, and glands. It provides strength and flexibility.

   • Hypodermis: This is the deepest layer, made up of fat and connective tissue. It helps insulate the body and absorbs shocks.

2. Types of Cells in the Epidermis:

   • Keratinocytes: These are the most common cells and are responsible for producing keratin, a protein that helps protect the skin.

   • Melanocytes: These cells make melanin, the pigment responsible for skin color. They help protect the skin from UV damage.

   • Merkel Cells: These are involved in the sense of touch and are found mostly in areas like fingertips.

   • Langerhans Cells: They are part of the immune system and help protect the skin from infections.

3. Epidermal Layers:

   • Stratum Basale: The deepest layer with a single layer of active cells that divide. It contains young keratinocytes, melanocytes, and Merkel cells.

   • Stratum Spinosum: A layer with a web-like structure that includes keratinocytes and Langerhans cells, providing strength and immunity.

   • Stratum Granulosum: This thick layer has 3-5 layers of modified keratinocytes that lose their nuclei and become more resistant to damage. Special substances help reduce water loss.

   • Stratum Lucidum: Found only in thick skin (like the palms and soles), this thin layer has clear, flat, dead keratinocytes.

   • Stratum Corneum: The topmost layer, about 20-30 cell layers thick, made of dead keratin-filled cells that help protect against wear and prevent water loss.

Understanding the integumentary system is crucial because it protects our bodies from harm and helps regulate temperature. It's like a shield that keeps everything inside safe!

Dermal Layer

• Structure: The dermis is the layer of skin beneath the outer skin layer (epidermis). It’s thick and contains all the important stuff like blood vessels, nerves, and hair follicles.

• Cells Present: There are a few types of cells in the dermis. The most common are fibroblasts, which make the skin strong and stretchy.

• Nervous and Vascular Supply: The dermis has lots of tiny blood vessels that keep your skin healthy and deliver oxygen. It also has nerves that help you feel things like heat, cold, and touch.

• Unique Modifications: Some parts of the dermis can have special structures like sweat glands that help cool you down, and sebaceous glands that produce oil to keep your skin moist.

Skin Appendages

• Skin appendages are things that come out from the skin, like hair and glands.

• Types of Sweat Glands:

  • Eccrine Glands: They are small and coiled, located mainly on your palms and the soles of your feet. They release sweat directly to your skin surface through tiny openings (pores) and help cool you off when you're hot.

  • Apocrine Glands: These are larger and are found in areas like your armpits and private parts. They empty into hair follicles and can cause odor because of the bacteria on your skin interacting with the sweat.

  • Ceruminous Glands: These are modified apocrine glands that produce earwax to protect your ear canal.

  • Mammary Glands: These are special glands that produce milk for babies.

Sebaceous Glands

• These glands are found in your skin and they produce oil (sebum). This oil helps keep your skin and hair from drying out.

Functions of the Integumentary System

The integumentary system (which includes your skin) has many important jobs:

• Protection: It acts like armor for your body, protecting you from germs and injuries.

• Body Temperature Regulation: It helps keep you cool when you're hot and warm when you're cold.

• Sensation: Your skin can feel things like touch, heat, and pain, which is important for keeping you safe.

• Metabolism: Your skin helps make vitamin D when you get sunlight, which is good for your bones.

• Excretion: It can remove some waste through sweat.

• Blood Reservoir: Your skin can hold extra blood and help manage how much blood goes to different parts of your body.

Sure! Let's break this down in a way that's easy to understand:

Types of Bone:

1. Spongy Bone: This is the light, airy bone which has lots of holes in it (like a sponge!). It makes bones lighter but still strong. You usually find it inside bones to help with strength and reduce weight.

2. Compact Bone: This is the hard, dense part of the bone that you can feel from the outside. It makes up the outer layer and provides strength and support.

Shapes of Bone:

1. Long Bones: These are bones that are longer than they are wide, like your arms and legs.

2. Short Bones: These are roughly cube-shaped, like the bones in your wrists and ankles.

3. Flat Bones: These are flat and thin, like your skull bones or ribs. They help protect your organs.

4. Irregular Bones: These bones don't fit into the other categories because they have unusual shapes, like your spine (vertebrae).

Anatomy of Long and Flat Bones:

• Diaphysis: This is the long, middle part of the bone (the shaft) that helps provide support.

• Epiphysis: These are the ends of the long bone that help connect with other bones—think of them as the end caps.

• Membranes: Bones have a covering called periosteum, which helps with healing and growth, and an inner layer called endosteum, which lines the inside.

Structure of an Osteon (the basic unit of bone):

• Concentric Rings (Lamella): Like layers of an onion, osteons have rings of bone tissue.

• Central Canal: At the center of the osteon is a hollow canal that carries blood vessels and nerves.

• Perpendicular Canals (Volkmann's): These connect different osteons to each other.

• Lacunae: Small spaces within the bone that house bone cells called osteocytes.

• Canaliculi: Tiny channels that run from lacunae to the central canal, allowing those bone cells to communicate and get nutrients.

Bone Composition:

Bones are made of a combination of minerals (like calcium) and proteins. This is what gives bones their strength and flexibility.

How Bones Are Formed:

Bones can form in a couple of ways - one way is from soft tissue (intramembranous ossification) and another from a cartilage model (endochondral ossification). But don't worry about the details right now!

Hormonal Control of Bone Health:

Hormones like PTH (Parathyroid Hormone) and calcitonin control how bones grow and repair. Think of hormones as messengers that tell your body how to maintain healthy bones.

Here are the answers to your Axial Skeleton questions:

1. Cranial Bones:

   • Paired:

     • Parietal: Located on the sides of the skull; functions to protect the brain and form the cranial cavity.

     • Temporal: Located on the lateral aspects of the skull; involved in protecting the temples and housing the structures of the inner ear.

   • Unpaired:

     • Frontal: Located at the forehead; protects the frontal lobe of the brain and forms the forehead and the upper part of the eye sockets.

     • Occipital: Located at the back of the skull; houses the occipital lobe and has the foramen magnum for the spinal cord.

     • Sphenoid: Located at the base of the skull; contributes to the cranial floor and has connections to many other bones.

     • Ethmoid: Located between the eyes; forms part of the nasal cavity and the orbit.

2. Cranial Sutures:

   • Coronal: Joins the frontal bone to the parietal bones.

   • Sagittal: Joins the two parietal bones.

   • Squamous: Joins the parietal bone to the temporal bone.

   • Lamboid: Joins the parietal bones to the occipital bone.

3. Facial Bones:

   • Unpaired:

     • Mandible: Lower jawbone, essential for chewing and holding teeth.

     • Vomer: Forms part of the nasal septum.

   • Paired:

     • Maxillae: Upper jawbones that support the teeth and form part of the eye sockets.

     • Zygomatics: Cheekbones that form the angles of the cheeks.

     • Nasals: Form the bridge of the nose.

     • Lacrimals: Small bones forming part of the eye socket,

     • Palatines: Form the back part of the hard palate.

4. Contributions to Anatomy:
   ### Bone Markings for Cranial and Facial Bones
   
   #### Cranial Bones:
   - **Parietal Bone**:
   - Markings: Sagittal suture, Coronal suture
   - **Temporal Bone**:
   - Markings: Squamous suture, Zygomatic process, Mastoid process, Styloid process
   - **Frontal Bone**:
   - Markings: Supraorbital foramen, Frontal sinus
   - **Occipital Bone**:
   - Markings: Foramen magnum, Occipital condyles, Nuchal lines
   - **Sphenoid Bone**:
   - Markings: Sella turcica, Pterygoid processes
   - **Ethmoid Bone**:
   - Markings: Cribriform plate, Crista galli, Perpendicular plate
   
   #### Cranial Sutures:
   - **Coronal Suture**: Joins frontal to parietal bones.
   - **Sagittal Suture**: Joins the two parietal bones.
   - **Squamous Suture**: Joins parietal to temporal bones.
   - **Lamboid Suture**: Joins parietal bones to occipital bone.
   
   #### Facial Bones:
   - **Mandible**:
   - Markings: Mandibular notch, Condylar process, Coronoid process
   - **Vomer**:
   - Marking: None specific
   - **Maxillae**:
   - Markings: Infraorbital foramen, Alveolar process
   - **Zygomatic Bone**:
   - Marking: Zygomatic arch
   - **Nasal Bones**:
   - Marking: None specific
   - **Lacrimal Bones**:
   - Marking: Lacrimal fossa
   - **Palatine Bones**:
   - Marking: Horizontal plates.

   • Various bones shape the dorsal, lateral, anterior, posterior, and ventral surfaces of the cranial vault and face.

   • They also contribute to the floor of the cranial vault, the eye orbit, and the nasal cavity.

5. Regions of the Vertebral Column:

   • Cervical: 7 vertebrae (C1-C7), supports the head and allows for neck movement.

   • Thoracic: 12 vertebrae (T1-T12), connects with the ribs to support the upper back.

   • Lumbar: 5 vertebrae (L1-L5), supports the lower back and bears a lot of weight.

   • Sacral: 5 fused vertebrae; supports the pelvis.

   • Coccyx: 4 fused vertebrae; known as the tailbone.

6. Anatomy of a Prototypic Vertebra:

   • Body: The thick front part that bears weight.

   • Vertebral Arch: Composed of:

     • Pedicle: Short, thick processes connecting the body to the arch.

     • Lamina: Flat plates forming the back of the arch.

   • Transverse Processes: Projections on either side for muscle attachment.

   • Spinous Processes: Projection that can be felt through the skin of the back.

   • Superior and Inferior Articular Processes: Allow for articulation with adjacent vertebrae.

   • Vertebral Foramen: The central canal that houses the spinal cord.

7. Unique Characteristics of Vertebrae:

   • Cervical: Smaller body, unique transverse foramen.

   • Thoracic: Longer spinous processes; articulate with ribs.

   • Lumbar: Larger body for supporting more weight.

8. Thoracic Cage:

   • Sternum: Composed of the manubrium, body, and xiphoid process.

   • Ribs: Includes vertebral ribs (11-12), vertebrochondral ribs (8-10), and vertebrosternal ribs (1-7).

   • Cartilages: Costal and intercostal cartilages for flexibility.

9. Articulations of Each Rib Type:

   • Thoracic Vertebrae: Each rib attaches to bodies and transverse processes of thoracic vertebrae.

   • Costal Cartilages: Attach ribs 1-7 to the sternum.

   • Intercostal Cartilages: Attach ribs 8-10 to the cartilage of rib 7.

10. Basic Anatomy of a Rib:

• Shaft: Long body of the rib.

• Head: Connects to the vertebrae.

• Neck: Narrow region just past the head.

• Tubercle: Projection that articulates with the vertebrae.

• Facet: Smooth surface for articulation.

Appendicular Skeleton

1. General Structure: The appendicular skeleton includes all the bones that support the limbs and the girdles that connect them to the axial skeleton.

2. Pectoral Girdle: Comprises the clavicles (collarbones) and scapulae (shoulder blades), providing attachment points for the upper limbs and facilitating a wide range of arm movements.

3. Pelvic Girdle: Formed by the hip bones (os coxae), it supports the weight of the upper body and connects the lower limbs to the axial skeleton, also forming a protective enclosure for the pelvic organs.

4. Upper Limb Structure: Consists of the humerus (arm), radius and ulna (forearm), carpals (wrist), metacarpals, and phalanges (hand), allowing for diverse movements and dexterity.

5. Lower Limb Structure: Includes the femur (thigh), patella (kneecap), tibia and fibula (leg), tarsals (ankle), and metatarsals and phalanges (foot), designed for weight bearing and movement during walking and running.

Proximal Row (from lateral to medial):

1. Scaphoid: The largest bone in the proximal row, located near the base of the thumb.

2. Lunate: Located next to the scaphoid, it has a crescent shape.

3. Triquetrum: Positioned next to the lunate, it is pyramidal in shape.

4. Pisiform: A pea-shaped bone that rests on top of the triquetrum.

Distal Row (from lateral to medial): 5. Trapezium: Located beneath the first metacarpal (thumb).

6. Trapezoid: Situated next to the trapezium, beneath the second metacarpal.

7. Capitate: The largest carpal bone, positioned centrally beneath the third metacarpal.

8. Hamate: Located beneath the fourth and fifth metacarpals, it is characterized by its hook-like projection.

Talus: The bone that sits above the calcaneus and forms the ankle joint with the tibia and fibula.

1. Calcaneus: Also known as the heel bone, it is the largest tarsal bone.

2. Navicular: Located in front of the talus, it helps form the arch of the foot.

3. Medial Cuneiform: The first of three cuneiform bones, located in front of the navicular.

4. Intermediate Cuneiform: The second cuneiform bone, located next to the medial cuneiform.

5. Lateral Cuneiform: The third cuneiform bone, situated next to the intermediate cuneiform.

6. Cuboid: Located on the lateral side of the foot, it articulates with the calcaneus and the fourth and fifth metatarsals.