Flashcards in Human Anatomy Midterm Review Deck (27)
Describe the importance of a standard anatomical position.
A standard anatomical position is a universal position or common point of reference for all who study the human body.
It allows all who study the body to discuss the parts of the body within the same frame of reference and experience.
What is the standard anatomical position?
The person is:
- standing upright
- facing the observer
- feet flat on the floor
- arms to the sides
- palms turned and facing forward (supinated)
What are the major planes and what type of section do they produce?
The major planes are:
Sagittal Plane, Frontal Plane, Transverse plane/Horizontal/Cross-sectional
The sagittal plane produces left and right sections.
The frontal plane produces anterior and posterior sections.
The transverse plane produces superior and inferior sections.
Parasagittal - uneven sections
Midsaggital/median - even halves
Describe the structure of a serous membrane. Identify the location of the 3 serous membranes of the body.
Serous membranes are thin membranes that line body cavities not open to the outside (ventral body cavities).
Composed of simple squamous epithelium called the mesothelium.
Serous membranes are composed of two continuous layers; the parietal and visceral layer.
The parietal layer lines the walls of cavities.
The visceral layer covers the viscera within these cavities.
The serous fluid in the space between the two layers reduces friction and allows the membranes to slide past each other.
- Parietal pleura - lines the thoracic cavity
- Visceral pleura - covers the lungs
- Parietal pericardium - lines the pericardial sac
-Visceral pericardium - covers the heart
- Parietal peritoneum - lines abdominal wall
-Visceral peritoneum - covers the abdominal viscera
How is epithelial tissue classified?
Epithelial tissue is classified by the number of layers, simple (1 layer) or stratified (2 or more layers) and, by the shape of the cells constituting the epithelium. These can be squamous, cuboidal or columnar.
The first name designates the number of layers, the second name designates the cell shape.
Squamous - flat
Cuboidal - cube shape
Columnar - column shaped
Furthermore, when it comes to stratified epithelia, the second name is based on the cell type on the superficial surface.
Finally, stratified can also be keratinized or non-keratinized, indicated at the beginning of the name.
Name the 6 special characteristics of epithelial tissue.
1 - Highly cellular
2 - Overlying connective tissue
3 - Avascular but innervated
4 - High capacity for regeneration
5 - Polarity
6 - Specialized contacts
Contrast simple epithelia with stratified epithelia.
Simple epithelium consists of only a single layer of cells, stratified epithelia is composed of multiple layers, 2 or more.
Simple epithelium has a function more suited for filtration, diffusion, lining viscera, secretion and absorption and propelling substances across membranes.
-Stratified epithelium has a function more suited for protection.
Stratified epithelia is more durable than simple epithelia
Simple epithelium is found lining the alveoli, as mesothelium and endothelium.
Stratified epithelium is found in locations subject to abrasion.
All the cells of simple epithelia are attached to the basement membrane
- Only the basal cells of stratified epithelia are attached to the basement membrane
All the cells of simple epithelium are the same (usually)
- Cells can be different throughout stratified epithelia
Why is areolar connective tissue considered to be the main battlefield in the fight against infection?
Areolar connective tissue underlies all epithelial tissue and is thus the first line of defense between the epithelial tissue and the blood stream.
Furthermore, areolar connective tissue contains multiple cells involved in immunity, including macrophages, WBC's and mast cells of the inflammation response.
Moreover, they contain all three fibre types (collagen, elastic, reticular) which function as a mesh to slow down the travel of invading microbes.
Compare and contrast dense regular and dense irregular CT.
Both derive from a similar embryonic origin (mesenchyme)
Both are a subset of CTP; Both are dense connective tissues.
Both contain fibroblasts and some elastic fibres
Both are connective tissues and thus are composed mostly of ECM rather than cells
Both are primarily composed of collagen fibres
Dense regular connective tissue consists of collagen fibres primarily arranged parallel to each other.
Dense irregular connective tissue on the other hand has collagen fibres arranged in perpendicular irregular arrangements.
Dense regular connective tissue is adapted to handle stress in only one direction
Dense irregular CT is adapted to handle tension in multiple directions.
Dense regular CT is poorly vascularized.
Dense irregular CT is vascularized.
Dense regular CT is found in ligaments and fascia.
Dense irregular CT is found in articular capsules.
Both have fibroblasts and some elastic fibres.
What do the 3 types of cartilage have in common? Name 1 location in the body where each would be found.
The three types of cartilage are: Fibrocartilage, Hyaline cartilage, Elastic cartilage.
They have the following in common:
- ECM is composed mostly of water (60-80%)
- Ground substance is gel-like
- Firm, flexible tissue
- Avascular and non-innervated
- Cell types are chondrocytes and chondroblasts
Fibrocartilage - pubic symphysis, intervertebral discs
Elastic cartilage - pinna of ear, epiglottis
Hyaline cartilage - articular cartilage, fetal skeleton
What type of CT underlies the epithelia in a mucous membrane? What is its specific name?
Areolar connective tissue.
Specifically named: lamina propria
Name the five strata in the epidermis, from top to bottom.
Describe, in detail, the stratum corneum.
23-30 cell layers thick of flat, dead keratinocytes filled with keratin
Cells are continuously shed
Topmost layer of skin
Protects the skin against abrasion and penetration
Describe, in detail, the stratum lucidum.
Composed of a few layers of flat, dead keratinocytes.
Only present in thick skin of the soles of the feet and palms of the hands.
See through under microscope.
Describe, in detail, the stratum granulosum.
1-5 cell layers of flat, dying keratinocytes
Third deepest skin strata
Contains lamellar granules that release waterproofing glycolipid
Describe, in detail, the stratum spinosum.
8-10 layers thick
Contains thick bundles of intermediate filaments
Contains star-shaped Langerhan's (macrophages) cells
Some mitotic division occurs here
Melanocytes are found here
Second deepest strata
Describe, in detail, the stratum basale.
Single layer of youngest keratinocytes that actively divide to replenish above cell layers
Receives nutrients and gases and removes wastes with the blood supply of underlying connective tissue
Attached to underlying dermis by dermal papillae
Contains some melanocytes
Name 1 function of the papillary layer and 1 function of the reticular layer of the dermis.
- contains dermal papillae which function to provide a blood supply for the overlying epidermis and increase surface area for exchanges and attachment between the two layers.
- composed of areolar connective tissue
-Composed of dense irregular connective tissue with interlacing collagen and elastic fibres
- this layer functions to provide the elasticity, strength, recoil and extensibility of the skin
What connective tissue is found in hypodermis?
Compare and contrast osteoblasts, osteocytes and osteoclasts.
- bone forming cells
- do not divide
- secrete matrix and collagen fibres
- initiate calcification
- once surrounded by their secretions, differentiate into osteocytes
- do not undergo cellular division
- mature cells that no longer secrete matrix
- lie in lacunae and are linked to one another through canaliculi
- Maintain the metabolism of the osteon
- Bone degrading cells
- Large cells with many nuclei and a ruffled
- Secrete concentrated HCl and release lysosomal enzymes for bone desorption
- originate from monocytes and macrophages
- All of these cells are actively involved in bone tissue
- Osteoclasts and osteoblasts are both involved in bone remodeling
- All of these cells do not divide
- Osteoblasts and osteocytes both are derived from osteoprogenitor cells (although osteocytes are derived from osteoblasts)
Identify 3 features of compact bone that contribute to its strength.
1 - Osteons within compact bone are arranged longitudinally and act as weight bearing pillars that reinforce the bone against compression and tension
2 - Lamellae are calcified collagen fibres that impart strength and are present in alternating clockwise-counterclockwise arrangements. These function to prevent torsional strain and crack propagation.
3 - Circumferential lamellae run along the circumference of the entire diaphysis in a similar anti-directional arrangement as lamellae. These function to resist torsion of the entire bone.
4 - Periosteum: contains dense irregular connective tissue which wraps around the compact bone. Imparts ability to withstand stress in multiple directions.
5 - Bone is a densely packed tissue
6 - Ground matrix is calcified, hard and provides structural strength
Compare and contrast the pectoral and pelvic girdle.
Which provides more flexibility? More stability?
- Both are ball and socket joints for limb articulation
- Both are girdles, i.e. they connect the appendicular skeleton to the axial skeleton
- Both are part of the appendicular skeleton
- consists of the clavicle and scapulae
- Does not completely encircle the body (i.e. the scapulae do not attach to one another or to the axial skeleton)
- Girdle is light and the limbs are mobile
-The socket of the shoulder joint (glenoid cavity) is hollow
Great for flexibility and mobility.
Poor for stability.
- consists of paired hip bones, (sacrum and coccux)
- attached to the axial skeleton by strong ligaments
- Completely encircles the body
- Heavier than the pectoral girdle
- Acetabulum is deep
-Provides less flexibility but more stability
How are joints classified functionally? Structurally? Give examples.
Joints are classified functionally by the amount of movement they allow. Functional classifications include:
Synarthrotic joints - immovable (ex: sutures)
Amphiarthrotic joints - partially movable (ex: interosseus membrane between radius and ulna)
Diarthrotic joints - freely movable (all synovial joints, eg. shoulder joint)
Joints are classified structurally by the material that binds the bones together as well as by the presence/absence of a joint cavity. Structural classifications include:
- Syndesmoses - amphiarthrotic, short or long
--eg. short - ligament between tibia and fibule
--eg. long - interosseus membrane between radius and ulna
- Gomphoses - synarthrotic
--eg. Periodontal ligament that holds teeth in jaw
- Sutures - synarthrotic
--eg. sutures in cranium
Synchondroses - synarthrotic
-eg. epiphyseal plate
Symphyses - amphiarthrotic
--eg. pubic symphysis
Synovial joints - diarthrotic and contain a joint cavity
- eg. shoulder joint
What is an articular disc? Give an example of a location in the body.
An articular disc or meniscus, is a disc of fibrocartilage which functions to:
- allow bones of different shapes to fit snuggly (eg. femur and tibia)
- makes joints more stable and minimizes wear and tear on joint surfaces
- distributes the load more evenly
- can partially or completely divide the joint cavity
Menisci are found in the knee for example.
Describe the 6 angular movements of synovial joints.
Abduction - movement of a limb along the frontal plane away from the midline
Adduction - movement of a limb along the frontal plane towards the midline
Flexion - movement along the sagittal plane that decreases the angle of the joint and brings the two articulating bones closer together
Extension - movement along the sagittal plane that increases the angle of the joint and brings the two articulating bones further apart
Hyperextension - movement along the saggital plane that involves bending a joint past its regular range of motion, past anatomical position.
eg. thorax, neck, shoulder, hip
Circumduction - combination of flexion, extension, abduction and adduction in no particular plane.
Describe the organization of skeletal muscle and its connective tissue sheaths.
Muscle fibres or cells, are surrounded by a fine sheet of endomysium, composed of areolar CT.
Muscle cells are then wrapped into fascicles, which are surrounded by a dense irregular CT layer called the perimysium.
Fasciscles are then wrapped together into a whole muscle. This is surrounded by a dense irregular connective tissue layer called the epimysium.