Intro to Human AnatomyChapter 1

What’s the Difference?

ANATOMY PHYSIOLOGY

Which has more new discoveries?

Anatomy or Physiology?

• To send a nerve impulse, sodium and potassium ions must switch places in the cell

• The human tailbone is a fusion of multiple vertebrae

• When the bicep muscle contracts, it pulls on tendons and ligaments which move the lower arm

Homeostasis

• Maintaining a stable internal environment

• Organ systems function to maintain homeostasis– Examples?

Homeostasis

• Homeostatic mechanisms work by:

1. Having a set point (normal, balanced)

2. Receptors in the body detect deviations or stimulus• Increase or decrease past the set point

3. Trigger a set of events to bring the situation back to normal

Blood Sugar Regulation

Homeostasis

• NEGATIVE FEEDBACK – Correction occurs opposite direction of stimulus– Examples:

• Body temp rises; cooling mechanisms activated• Body temp drops; heating mechanisms activated

– Other examples?

Homeostasis

• POSITIVE FEEDBACK - Stimulus amplifies response in the same direction

– Examples:• Chemicals present in a blood clot lead to more clotting• A baby drinking mother’s milk causes more milk

production• Pressure in the uterus during childbirth leads to stronger contractions

Homeostasis

• VITAL SIGNS– A measure of homeostasis– Indicate that someone is alive

• What is measured in a test of vital signs?

Organization of the Body

• Lots of vocabulary to describe the body– Why?

• Allows doctors to communicate as clearly as possible

– Which would you rather hear as a surgeon?• “It hurts in the left upper side of my chest.”• “I’m having pain in the left lateral pleural cavity,

superior to the heart.”

Organization of the Body

• Many body cavities lined by membranes

PARIETAL –

lines body cavity

VISCERAL –

covers organ

Organization of the Body

• Always refer to body in ANATOMICAL POSITION– Face forward– Palms forward– Note: Right and left

refer to the patient

Organization of the Body

• To observe different sections, we cut the body along various imaginary planes

– SAGITTAL (median)– FRONTAL (coronal)– TRANSVERSE

(horizontal)

Organization of the Body

What does this mean?

The lesion is located in the right thorax just lateral to

the mid-sagittal plane.