anatomy midterm study guide

Anatomical Position

Hands at the sides with palms facing forward and feet together

Sagittal Plane

divides body into left and right

Frontal/Coronal Plane

divides the body into anterior and posterior parts

Transverse Plane

divides the body into superior and inferior parts

Anterior/Ventral

front of the body

Posterior/Dorsal

back of body

Medial

Toward the midline of the body

Lateral

Away from the midline of the body

Superior

above

Inferior

below

Proximal

Nearer to the trunk of the body

Distal

Farther from the trunk of the body

Cranial

toward the head

Caudal

toward the tail

Superficial

near the surface

Deep

away from the surface

axillary

pertaining to the armpit

carpal

pertaining to the wrist

right hypochondriac region

upper right region

epigastric region

upper middle region

left hypochondriac region

top left region

right lumbar region

middle right region

Umbilical region

The centermost region, includes the umbilicus

left lumbar region

left middle region

right iliac region

lower right region

hypogastric region

lower middle region

left iliac region

lower left region

Anatomy

The study of body structures and their relationship to other body parts

Physiology

The study of how those body parts function

Principle of complementarity

Certain structures perform specific functions and vice versa (“form follows function”)

Homeostasis

• Maintaining a stable internal environment

• Made possible by feedback mechanisms (negative and positive)

Molecular

1st level of organization

Cellular

2nd level of organization

Tissue

3rd level of organization

Organ

4th level of organization

Organ System

5th level of organization

Organism

6th level of organization

Negative Feedback

Counteracts a change

• Ex. thermoregulation

Positive Feedback

Exaggerates or enhances the original change

• Ex. Childbirth, Blood Clotting

Sliding filament theory

A theory that explains how muscles contract by the sliding of actin and myosin filaments past each other.

1. Signal & Calcium Release: A nerve impulse triggers the release of calcium into the muscle fiber. 

2. Binding Site Exposure: Calcium binds to troponin, shifting tropomyosin and exposing the myosin-binding sites on the actin

3. Cross-Bridge Formation: Myosin heads attach to the exposed sites on actin

4. Power Stroke: ADP and phosphate are released, causing the myosin head to pivot and pull the actin filament towards the sarcomere's center

5. Detachment & Reattachment: A new ATP molecule binds to the myosin head, causing it to detach; the ATP breaks down, re-energizing the head to repeat the cycle

Neuromuscular junction

Contains:

• Axon

• Synaptic cleft

• Possynaptic membrane

• ACh

The site where skeletal muscles must be stimulated to contract, receiving an electrical signal from the nervous system through a motor neuron.

Motor unit

One motor neuron and all the skeletal muscle cells stimulated by that neuron.

Twitch

A single cycle of stimulus-contraction-relaxation in a muscle fiber.

Rigor Mortis

• Begins 2-7 hours after death, and lasts until decomposition begins (1-6 days after death)

• calcium leaks out of storage and into sarcoplasm of muscle fibers, stimulating myosin to form cross-bridges with actin.

• ATP is used up so myosin cannot detach

• Skeletal muscles become locked in contracted position

Perimysium

Label B on the muscle tissue

Epimysium

Label C on the muscle tissue

Muscle fiber (cell)

Label D on the muscle tissue

Fascicle

Label E on the muscle tissue

Endomysium

Label F on the muscle tissue

Action potential

Label A on the neuromuscular junction

Synaptic vesicle

Label B on the neuromuscular junction

Synaptic cleft

Label C on the neuromuscular junction

Acetylcholine (ACh)

Label D on the neuromuscular junction

Acetylcholine (ACh) receptor

Label E on the neuromuscular junction

Actin

The protein strands that get pulled (Thin Filaments)

Mysoin

Have "heads" that bind to actin (Thick Filaments)

Characteristics of Muscle Tissue

Contractility: The ability to shorten and thicken.

Irritability/Excitability: The ability to receive and respond to stimuli.

Extensibility: The ability to stretch.

Elasticity: The ability to return to its original shape.

synarthroses

immovable joints

• Ex. Skull sutures, tooth joints

amphiarthroses

slightly movable joints

• Ex. Pubis symphysis, intervertebral discs

hinge joints

Ex. elbow, knee

intervertebral discs

contain gel-like nucleus pulposus and cartilaginous annulus fibrosus

diarthroses

freely movable joints

• Ex. Shoulder, hip, knee, elbow, wrist

plantar flexion

pointing the toes down produces this motion

abduction

moving laterally

inversion

turning the bottom of the foot medially

flexion

decreasing the angle of a joint

eversion

turning the bottom of the foot laterally

supination

turning the palm facing upward

dorsiflexion

pointing toes up produces this motion

ball-and-socket joints

Ball-shaped end of one bone fits into rounded socket of the other

• Allow movement in all axes (including rotation); mostly freely

moving synovial joints

• Ex. Shoulder, hip

pronation

turning the palm facing downward

Bursa

fluid-filled sac that acts as a cushion between bones, muscles, tendons, and skin to reduce friction and allow smooth movement in joints

Extension

increases the angle between body parts at a joint

Adduction

moving toward the midline of the body

Arthiritis

“joint inflammation”

Herniated disc

The nucleus pulposus (soft, jelly-like center of a spinal disc) has broken through the surrounding annulus fibrosus and can compress spinal nerves, irritating nearby nerves and causing pain, numbness, or weakness

Bulging disc

Nucleus pulposus flattens and bulges outward, possibly entering the vertebral canal, with its outer layer remaining intact, often due to aging or wear and tear

diaphysis

long shaft of a bone

epiphysis

end of a bone

periosteum

• fibrous membrane covering a bone

• contains blood vessels and nerves that supply the bone with nutrients and sensation

short

bones that have similar length and width

• Ex. Carpals

canaliculi

connections between lacunae so fluid can travel between them

parathyroid hormone (PTH)

hormone that raises calcium in the blood

hematoma formation

step one of fracture repair

soft callus formation

step two of fracture repair

bony callus formation

step three of fracture repair

remodeling

step four of fracture repair

osteoblasts

bone building cells

long

bones that have a greater length than width

Ex. Humerus, Femur

epiphyseal plate

• In children, it separates the epiphysis from the diaphysis => bone growth

• At puberty, this cartilage gradually narrows until it disappears completely and closes, forming an epiphyseal line

central canal

location of blood vessels and nerves in an osteon

osteoclasts

cells that break down bone

open/compound

type of fracture that breaks the skin

comminuted

type of fracture that shatters the bone

lamellae

• rings of bone that encircle the central canal of an osteon

• made of mineralized matrix and collagen fibers

• provide strength and rigidity

osteocytes

• cells found in lacunae

• originally, osteoblasts that become embedded in the bone matrix

• mechanosensors

lacunae

• small areas of fluid between lamellae

• housing/protection for osteocytes

exercise, diet, hormones

factors that affect bone remodeling

flat

• thin, broad bones (wider than they are long)

• protect internal organs

• provide surfaces for muscle attachment

• Ex. Cranial bones (frontal, parietal, occipital, etc), and ribs

irregular

• bones with an odd shape

• Ex. Vertebra