First Exam Anatomy and Physiology

Anatomy

study of the structure of body parts and their relationship to one another

Physiology

study of the function of body parts how they work to carry out life sustaining activities

Superior (cranial)

towards the head end or upper part of a structure or the body above

example: The head is superior to the abdomen

Inferior (caudal)

away from the head end or towards the lower part of a structure or the body: below

example the naval is inferior to the chin

Anterior (ventral)

toward or at the front of the body; in front of

example: the breastbone is anterior to the spine

Posterior (dorsal)

toward or at the back of the body: behind

example the heart is posterior to the breastbone

medial

toward or at the midline of the body on the inner side of

example: the heart is medial to the arm

lateral

away from the midline of the body on the outer side of

example the arms are lateral to the chest

intermediate

between a more medial and a more lateral structure

example: the collarbone is intermediate between the breastbone and shoulder

Proximal

closer to the origin of the body part of the point of attachment of a limb to the body trunk

example: the elbow is proximal to the wrist

Distal

father from the origin of a body part or the point of attachment of a limb to the body trunk.

example: The knee is distal to the thigh

Superficial (external)

toward or at the body surface

example: The skin is superficial to the skeletal muscles

Deep (internal)

away from the body surface: more internal

example: the lungs are deep to the skin

Sagittal plane

Divides body vertically into right and left parts. Produces a sagittal section if cut along this plane

Midsgaital (median) plane

cut was made perfectly on midline

Parasagittal plane

cut was off centered, not on midline

Frontal (coronal plane)

divides body vertically into anterior and posterior parts (front and back).

Produces a frontal or coronal section

Transverse (horizontal) plane

divides body horizontally (90° to vertical plane) into superior and inferior parts (top and bottom). Produces a cross section

Axial

head, neck and trunk

Appendicular

limbs

Four Abdominopelvic Quadrants

Maintaining boundaries

separation between internal and external environments’s must exit
plasma membranes separate cells
skin separates organism from environment

Movement

muscular system allows movement

of body parts via skeletal muscles. Of substances via cardiac muscle (blood) and smooth muscle (digestion or urination )

Responsiveness

ability to sense and response to stimuli. withdrawal reflex prevent injury. control breathing rate, which must change in response to different activities

Digestion

breakdown of ingested foodstuffs, followed by absorption of simple molecules into blood

Metabolism

all chemical reactions that occur in body cells.

catabolism

breakdown of molecules

anabolsim

synthesis of molecules

Excretion

removal of wastes from metabolism and digestion.

Urea (from breakdown of proteins) carbon dioxide (from metabolism) and feces (unabsorbed foods)

Reproduction

at the cellular level reproduction involves division of cells fro growth or repair

at the organismal level, reproduction is the production of offspring

Growth

increase in size of a body part or of organism

What do human need to survive?

Human need many different factors in order to survive, but need to be appropriate amounts; too much or too little can be harmful

• nutrients

• oxygen

• water

• normal body temp

• appropriate atmospheric pressure

How do we maintain appropriate levels of these requirement?

Homestasis

Homestasis

is the maintenance of relatively stable internal condition despite continuous changes in environment.

A dynamic state of equilibrium, always readjusting as needed. Maintained by contribution of all organ system

Homeostatic controls

Body must constantly be monitored and regulated to maintain homeostasis

• nervous and endocrine system, as well as others play a major role in maintaining homeostasis

• Variable are factors that can change (blood sugar, body temp, and blood volume)

Receptor (sensor)

monitor environment

responses to stimuli (thing that cause changes in controls variables)

Control center

determine set point at which variable is maintained

receives input from receptor

determines appropriate response

Brain or spinal cord

Effector

receives output from control center, provides the means to respond, response either reduces stimulus (negative feedback) or enhances stimulus (positive feedback)

Negative feedback

most used mechanism in body. Response reduces or shut off original stimulus

variable changes in opposite direction of initial change

negative feedback examples (Blood Glucose)

Receptors sense increased blood glucose (blood sugar)

Pancreases (control center) compares level to set point and secretes insulin into the blood

Insulin causes body cells (effectors) to absorb more glucoses, which decrease blood glucose levels

Positive feedback

response enhances or exaggerates the original stimuli

may exhibit a cascade or amplifying effect as a feedback causes variable to continue in same direction as initial change

Positive feedback examples

enhancement of labor contraction by oxytocin

platelet plug formation and blood clotting

Integumentary system

skin (largest organ of the body)

surface area= 20 square feet

weight= 10 pounds

Skin (protection)

Skin is exposed to microorganism, abrasions, temperature extremes, and harmful chemicals

3 barriers are chemical, physical and biological

Chemical barrier

skin secretes many chemicals such as:

sweat, which contains antimicrobial protein (defensin)

Sebum and defensins, which kill bacteria

Melanin provides a chemical barrier against UV radiation damage

Acid mantle

low pH of skin inhibits bacterial multiplication

Physical barriers

flat dead, keratinized squamous cells of stratum corneum, surrounded by glycolipids, block most water and water soluble substances

Physical barriers (some chemical have limited penetration of skin)

lipid-soluble substances

plant oleoresins (poison ivy)

organic solvents (acetone or paint thinner)

salts of heavy metals (lead, mercury)

Physical barriers (administration route of medication/drugs)

nitroglycerin

nicotine

fentanyl

estrogen and testoerone

Biological barriers

cells breakdown biological invader and activate immune system

epidermis (contains dendritic cells)

dermis (contains macrophages)

Integumentary stem is made up:

1. skin

2. accessory organs

• Hair

• nails

• glands

  • sweat

  • sebaceous

• Sensory Receptors

Epidermis

superficial region (surface)

consists of epithelia tissues and is avascular (no blood vessels)

Dermis

underlies (deep) epidermis

mostly fibrous connective tissues and vascular

contains accessory organ structures

Hypodermis

subcutaneous layer deep to skin

not part of skin but shares some functions

mostly adipose tissues that absorbs shock and insulates

anchors skin to underlying structures (most muscles)

Cells of the Epidermis

consist mostly of keratinized stratified squamous epithelium

Four cell types

1. Keratinocytes

2. Melanocytes

3. Dendritic (langerhans) cells

4. Tactile (Merkel cells)

1. Keratinocytes

• Produce fibrous keratin (protein that gives skin its protective properties)

• Major cells of epidermis

• Tightly connected by desmosomes

• Millions slough off every day

2. Melanocytes

Spider-shaped cells located in deepest epidermis

• Produce pigment melanin:

  • Melanin is transferred to keratinocytes, where it protect the nucleus from UV damage

3. Dendritic (langerhans) cells

star-shaped macrophages that patrol deep epidermis

• Are key activators of immune system 

4. Tactile (Merkel) Cells

sensory receptors that sense touch

Layers of the Epidermis

Thick skin contains five layers (strata) and is found in high-abrasion areas (hands, feet)

• Thin skin contains only four strata

• Five layers of skin:

1. Stratum basale

2. Stratum spinosum

3. Stratum granulosum

4. Stratum lucidum (only in thick skin)

5. Stratum corneum

Stratum Basale (basal layer)

Deepest of all epidermal layers (base layer)

• Layer that is firmly attached to dermis

• Consists of a single row of stem cells that actively divide

  • One cell is pushed superficially from basal layer to surface,

  • Cell dies as it moves toward surface

• Contains melanocytes, tactile cells

Stratum Spinosum (prickly layer)

Several cell layers thick

• Cells contain desmosomes

  • Allows them to resist tension and pulling

• Keratinocytes in this layer appear spikey, so they are called prickle cells

• Scattered among keratinocytes are abundant melanosomes and dendritic cells

Stratum Granulosum (granular layer)

Four to six cells thick, but cells are flattened, so layer is thin

• Cell appearance changes

  • Cells flatten, nuclei and organelles disintegrate

  • Keratinization begins

  • Cells also accumulate  a water-resistant glycolipid that slows water loss

• Cells above this layer die

  • Too far from dermal capillaries to survive

Stratum Lucidum (clear layer)

found only in thick skin ( hands, soles of feet)

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

• Lies superficial to the stratum granulosum

Stratum Corneum (horny layer)

Rows of flat, anucleated, keratinized dead cells

• Accounts for three-quarters of epidermal thickness

• Though dead, cells still function to:

  • Protect deeper cells from the environment

  • Prevent water loss

  • Protect from abrasion and penetration

  • Act as a barrier against biological, chemical, and physical 

Apoptosis

cells change by going through controlled cell death

dead cells slough off and are replaced by deeper cells

Humans can shed- 50,00 cells every minutes

Demis

strong flexible connective tissue

vascular (blood vessels and lympatic vessels)

contains nerves

contains hair follicles, sebaceous glands and sweat galnds

two layer (papillary and reticular)

Papillary layer

Superficial layer of connective tissue consisting of loose, interlacing collagen and elastic fibers and blood vessels

• Dermal papillae: superficial region of dermis that sends fingerlike projections up into epidermis

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

Papillary layer (in thick skin)

• dermal papillae lie on top of dermal ridges, which give rise to epidermal ridges

  • Collectively ridges are called friction ridges 

    • Enhance gripping ability 

    • Contribute to sense of touch 

    • Sweat pores in ridges  

Reticular layer

• Makes up ~80% of dermal thickness

• Consists of coarse, dense fibrous connective tissue

  • Many elastic fibers provide stretch-recoil properties

  • Collagen fibers provide strength and resiliency

    • Bind water, keeping skin hydrated

• Network of blood vessels that run between reticular layer and hypodermis

Cleavage (tension) lines

• in reticular layer are caused by many collagen fibers running parallel to skin surface

  • Externally invisible

  • Important to surgeons because incisions parallel to cleavage lines heal more readily

Flexure lines

• of reticular layer are dermal folds at or near joints

  • Dermis is tightly secured to deeper structures

  • Skin’s inability to slide easily for joint movement causes deep creases

  • Visible on hands wrists, fingers, soles, toes

Hair

• (also called pili): flexible strands of dead, keratinized cells

• Produced by hair follicles

• Contains hard keratin, not like soft keratin found in skin

  • Hard keratin is tougher and more durable, and cells do not flake off

• Functions: 

  • Hair on head guards against physical trauma

  • Protect from heat loss

  • Shield skin from sunlight

Nails

• Scale-like modifications of epidermis that contain hard keratin

• Act as a protective cover for distal, dorsal surface of fingers and toes

• Abnormal color or shape can be an indicator of disease

Eccrine Sweat Glands

• Most abundant type

  • High density on palms, soles, and forehead

• Ducts connect to pores

• Function in thermoregulation

  • Regulated by sympathetic nervous system

• Secretion of sweat

  • 99% water, salt, vitamin C, antibodies, dermcidin (microbe-killing peptide) metabolic wastes

Apocrine Sweat Glands

• Confined to axillary and anogenital areas

• Secrete viscous milky or yellowish sweat that contains fatty substances and proteins

  • Bacteria break down sweat, leading to body odor

• Larger than eccrine sweat glands with ducts emptying into hair follicles

• Modified apocrine glands

  • Ceruminous glands: lining of external ear canal; secrete cerumen (earwax)

  • Mammary glands: secrete milk

Sebaceous (Oil) Glands

• widely distributed, except for thick skin of palms and soles

• Most develop from and secrete into hair follicles

• Relatively inactive until puberty

  • Stimulated by hormones, especially androgens

• Secrete sebum

  • Oily secretion 

  • Bactericidal (bacteria-killing) properties

  • Softens hair and skin

Melanin

• Pigment made in skin; made by melanocytes (two forms: reddish yellow to brownish black)

• Packaged into melanosomes that are sent to shield DNA of keratinocytes from damaging UV sunlight

• The more sun the more melanin will be produced

• Skin color differences are due to amount and form of melanin

• Freckles and pigmented moles are local accumulations of melanin

Carotene

yellow to orange pigment

most obvious in palms and soles

accumulates in stratum corneum and hypodermis

Hemoglobin

pinkish hue of fair skin (main coloring in those with lower levels of melanin)

Homeostatic imbalance

• Cyanosis

  • Blue skin color: low oxygenation of hemoglobin

• Pallor (blanching or pale color)

  • Anemia, low blood pressure, fear, anger

• Erythema (redness)

  • Fever, hypertension, inflammation, allergy

• Jaundice (yellow cast)

  • Liver disorders

• Bruises (black-and-blue marks)

  • Also referred to as ecchymoses or hematomas, are a result of clotted blood beneath skin

  • As clot is broken down, color of bruise changes

• Brown or black “necklace” or bruises

  • Hyperpigmented dark areas in axillae and around neck may be a sign of insulin resistance and elevated blood glucose levels

Skin cancer

• Most skin tumors are benign (not cancerous) and do not spread (metastasize)

• Risk factors

  • Overexposure to UV radiation

Three major types of skin cancer

• Basal cell carcinoma

• Squamous cell carcinoma

• Melanoma

Basal cell carcinoma

• Least malignant and most common

• Stratum basale cells proliferate and slowly invade dermis and hypodermis

Squamous cell carcinoma

Second most common type; can metastasize

• Involves keratinocytes of stratum spinosum

• Usually is a scaly reddened papule on scalp, ears, lower lip, or hands

Melanoma

Cancer of melanocytes; is most dangerous type because it is highly metastatic and resistant to chemotherapy

What does our skeletal system do?

support, protection, movement, mineral and growth factors, blood cell formation (hemotopoesis), triglyceride (fat) storage (used for an energy source, is stored in bone cavities, and Hormone production

How many bones do we have?

206 named bones in human skeleton

86 paired (having left and right0 34 paired

Long bones

longer than they are wide

limb bones

Short bones

cube shaped bones (in wrist and ankle)

Sesamoid bones form within tendons (example patella)

vary in size and number in different individuals

Flat bones

thin flat slightly curved

sternum, scapulae’s, ribs and most skull bones

irregular bones

complained shaped

vertebrae and hip bones

Osseous

bone tissues predominates, but a bone also has nervous tissue, cartilage, fibrous connective tissue, muscle cells, and epithelial cells in its blood vessels

2 region of osseus

1. Compact bones

2. Spongy bones

Compact bones

dense outer layer on every bone that appears smooth and solid

Spongy bone

• made up of a honeycomb of small, needle-like or flat pieces of bone called trabeculae

• Open spaces between trabeculae are filled with red or yellow bone marrow

Structure of typical long bones

• Diaphysis: tubular shaft that forms long axis of bone

  • Consists of compact bone surrounding central medullary cavity that is filled with yellow bone marrow in adults

• Epiphyses: at the proximal and distal ends of long bones -consists of compact bone externally and spongy bone internally

  • Articular cartilage covers articular (joint) surfaces

• Between diaphysis and epiphysis is epiphyseal line

  • Remnant of childhood epiphyseal plate (growth plate) – a disc of hyaline cartilage

Structure of short, irregular, and flat bones

Consist of thin plates of spongy bone covered by compact bone

• Compact bone sandwiched between connective tissue membranes

  • Periosteum covers outside of compact bone, and endosteum covers inside portion of compact bone

• Bone marrow is scattered throughout spongy bone; no defined marrow cavity

• Hyaline cartilage covers area of bone that is part of a movable joint

Periosteum

double-layered membrane that covers outer surface expect joints

contains many nerve fibers and blood vessels that continue to the shaft through nutrient foramen openings

anchoring points for tendons and ligaments

Fibrous layer

outer layer consisting of dense irregular connective tissue that secure to bone matrix

osteogenic layer

inner layer abutting bone and contains primitive osteogenic stem cells that give rise to most bone cells '