A+P Quiz 1

Anatomic Positions/Directional Terms and Integumentary System

Anatomical Position

body erect (standing), feet slightly apart, palms facing forward, thumbs pointing away from body

Directional terms

describe one body structure in relation to another, right and left refer to the body being viewed

Superior and inferior

top and bottom (above or below)

superior and inferior examples

the neck is superior to the thorax (chest cavity)

the diaphragm is inferior to the lungs

anterior and posterior /

ventral and dorsal

front and back

anterior and posterior examples

the sternum is anterior to the heart

the spine is posterior to the abdominal cavity

medial and lateral

near the midline and away from the midline of the body

general structures

medial and lateral examples

the heart is medial to the left lung

the ears are lateral to the nose

superficial and deep

close to the surface or farther away from the surface

superficial and deep examples

the skin is superficial to bone

the dermis is deep to the epidermis

proximal and distal

specific to limbs

close to body-origin or far from body-origin

dorsal and palmar

specific to the hand

dorsal = back of hand

palmar = front of hand

dorsal and plantar

specific to the foot

dorsal = top of foot

plantar = bottom of foot

two major divisions of the the body

axial and appendicular

axial definition

head, neck, and trunk

appendicular definition

limbs (arms and legs)

eight major body regions

cephalic/cranial (head), cervical (neck), back/dorsal, thoracic (chest cavity), abdominal, pelvic/pubic, upper limbs, lower limbs

body planes

surfaces along which body or structures may be cut for anatomical study

three most common planes

sagittal plane

frontal (coronal) plane

transverse (horizontal) plane

sections

cuts or sections made along a body plane

a sagittal cut makes a sagittal section

sagittal plane

divides the body vertically into right and left parts

midsagittal (median) plane

cut made perfectly on the midline

head to toe view

parasagittal plane

cut off center, not exactly on midline

frontal (coronal) plane

divides body vertically into anterior and posterior parts

produces a frontal or coronal section

transverse (horizontal) plane

divides body horizontally (perpendicular to vertical plane) into superior and inferior parts

produces a cross section

used in CT and MRI scans

oblique section

result of cuts and any angle other than 90 deg to vertical plane

diagonal cut

no commonly used

body cavities

internal cavities that are closed to the environment

provide varying degrees of protection to organs within

two sets of body cavities

dorsal body cavity and ventral body cavity

dorsal body cavity

holds the central nervous system

made up of cranial and vertebral cavities

cranial cavity

encases the brain

vertebral cavity

encases the spinal cord

ventral body cavity

holds internal organs (viscera)

made up of thoracic and abdominopelvic cavities (separated by the diaphragm)

thoracic cavity

surrounded by ribs and muscles of the chest

made up of two lateral pleural cavities and the mediastinum

pleural cavities

each envelops a lung

mediastinum

made up of the pericardial cavity and the superior mediastinal cavity

pericardial cavity

encloses the heart

superior mediastinal cavity

surround other thoracic organs (esophagus, trachea)

abdominopelvic cavity

made up of abdominal cavity and pelvic cavity

divided into quadrants

abdominal cavity

contains stomach, liver, intestines, and spleen

pelvic cavity

contains the urinary bladder, reproductive organs, and rectum

abdominopelvic quadrants

RUQ, LUQ, RLQ, LLQ

used by providers

RUQ

contains liver and gallbladder

LUQ

contains stomach and spleen

RLQ

contains appendix and ovaries

LLQ

contains large intestine

abdominopelvic regions

nine regions used by anatomists

right hypochondriac region, epigastric region, left hypochondriac region

right lateral (lumbar) region, umbilical region, left lateral (lumbar) region

right inguinal (iliac) region, pubic (hypogastric) region, left inguinal (iliac) region

ventral cavity membranes

called serosa or serous membrane

thin, double-layered membranes that cover surfaces in ventral body cavity

parietal serosa

lines internal body cavity walls

visceral serosa

covers internal organs (viscera)

serous fluid

fills the slit-like cavities that separate double-layered membranes

fluid is secreted by both layers

3 main serous membranes

pleura, pericardium, and peritoneum

pleura

found in the thoracic cavity

surrounds the lungs in the pleural cavity

pericardium

found in the thoracic cavity

surrounds the heart and blood vessels in the pericardial cavity

peritoneum

found in the abdominopelvic cavity

surrounds the abdominal cavity

other body cavities that are smaller and exposed to the environment

oral and digestive cavities

nasal cavity

orbital cavities

middle ear cavity

other body cavities that are smaller but not exposed to the environment

synovial cavities (joint cavities)

two skin regions

epidermis and dermis

additional region that is technically not part of the skin

hypodermis (superficial fascia)

epidermis

superficial region

consists of epithelial tissue

avascular

dermis

underlies the epidermis

mostly fibrous connective tissue

vascular

hypodermis

subcutaneous layer deep to the skin

shares some functions with the skin

made up of adipose tissue

absorbs shock, insulates, and anchors skin to underlying tissues

the epidermis consists mostly of

keratinized stratified squamous epithelium

cells of the epidermis

keratinocytes, melanocytes, dendritic (Langerhans) cells, and tactile epithelial (Merkel) cells

keratinocytes

most abundant cells in the epidermis

produce keratin

migrate superficially and flatten out over time

desmosomes

tie together keratinocytes and keeps them from coming apart

melanocytes

spider/octopus-shaped cells in the basal layer

produce melanin which protects the cells nucleus from UV damage

melanosome

melanin is packaged into them and transferred to keratinocytes where the melanin is then released

dendritic (Langerhans) cells

star-shaped macrophages that patrol deep epidermis

activate the immune system

dendritic extensions create continuous networks between themselves through keratinocytes

tactile epithelial (Merkel) cells

sensory receptors in the basal layer that sense touch and light pressure

each is attached to a sensory nerve ending

connects to the nervous system

layers of the epidermis

stratum basale (basal layer) (deep)

stratum spinosum (spinous/prickly layer)

stratum granulosum (granular layer)

\*stratum lucidum (only in thick skin)

stratum corneum (visible skin) (most superficial)

stratum basale (basal layer)

deepest layer

thinnest layer (single row of stem cells)

firmly attached to dermis

contains mostly melanocytes

also contains tactile epithelial cells

basal stem cells

actively mitotic

produce two daughter cells

one daughter cell is pushed out to become a keratinocyte

one daughter cell remains as a basal stem cell

stratum spinosum

several layers thick

keratinocyte cells contain weblike systems of intermediate prekeratin filament

each keratinocyte is attached to the surrounding keratinocytes by many desmosomes

slide cells appear spikey due to these connections

dendritic cells are most abundant in this layer

stratum granulosum

several layers thick

cells are flattened so layer is thin

where keratinzation beings

keratohyaline granules

accumulated by cells

help form keratin fibers in upper layers

lamellar granules

accumulated by cells

water-resistant glycolipid

slows water loss from the skin

cells above this layer die

stratum lucidum

only found in thick skin (palms and soles)

thin, translucent band of two to three rows of clear, flat, dead keratinocytes

first dead layer

stratum corneum

thickest layer of the epidermis (3/4 of epidermal thickness)

flat, anucleate, keratinized dead cells

acts as a barrier to protect from environment, water loss, abrasion, penetration, chemical, biological, and physical assaults

apoptosis

controlled cell death

how cells change

dermis

strong, flexible connective tissue

semifluid matrix embedded with fibers binding your entire body together

cells of the dermis

fibroblasts, macrophages

occasionally mast cells and white blood cells

accessories of the dermis

nerves, blood vessels, and lymphatic vessels

epidermal hair follicles, oil glands, and sweat glands

layers of the dermis

papillary layer and reticular layer

papillary layer

makes up about 20% of the dermal layer

superficial layer of areolar connective tissue

papillary layer contains

loose, interlacing collagen and elastic fibers and blood vessels

dermal papillae

superficial region of dermis that send fingerlike projection into the epidermis

papillae contain

capillary loops, free nerve endings, and touch receptors called tactile (Meissner’s) corpuscles

epidermal ridges

found in thick skin

created by dermal papillae which lie on top of dermal ridges

friction ridges

all the collective ridges

functions of friction ridges

enhance gripping ability

contribute to sense of touch

sweat pores in ridges leave unique fingerprint pattern

reticular layer

makes up about 80% of dermal thickness

the reticular layer consists of

coarse, dense fibrous connective tissue

elastic fibers → stretch/recoil properties

collagen fibers → strength and resiliency

reticular layer contains

dermal vascular plexus (network of blood vessels between reticular layer and hypodermis)

cleavage lines

flexure lines

cleavage (tension) lines

caused by many collagen fibers running parallel to skin surface

represent separations between underlying collagen fiber bundles in the reticular dermis

important for incisions → parallel incisions to cleavage lines heal better

flexure lines

dermal folds at or near joints

dermis is tightly secured to deeper structures

visible on hands, wrists, fingers, soles, toes

pigments that contribute to skin color

melanin, carotene, and hemoglobin

melanin

only pigment made in the skin

melanocytes

make melanin

melanosomes

what melanin is packaged into and sent out

forms of melanin

reddish yellow to brownish black