Anatomy- Chapter 1: The Human Body Orientation

ANATOMY

study of structure (body parts)

Subdivision of Anatomy- GROSS/ MACROSCOPIC

the study of body structures visible to the naked eye. ( heart, lungs, kidneys, etc.) (EX: regional, systemic, and surface anatomy)

Subdivision of Anatomy- MICROSCOPIC

the study of body structures that cannot be seen without magnification, such as cells and tissues. (EX: cytology and histology)

Subdivision of Anatomy- DEVELOPMENTAL

the study of the structural changes that occur in the body throughout the life span, from conception to maturity. (EX: embryology)

PHYSIOLOGY

study of the function of the body (how things work)

Subdivisions of physiology based on functions of organ systems

skeletal, muscular, nervous

ANATOMY & PHYSIOLOGY ARE INSEPERABLE

function always reflects structure ( muscles (structure) contract (function) so your body can move

LEVELS OF STRUCTURAL ORGANIZATION

group of atoms= molecules, group of molecules= cells, group of SAME cells= tissue, group of different types of tissue= organ, group of different organ= organ system, organ system that works closely together= organismal

Necessary Life Function: MAINTAINING BOUNDARIES b/t external & internal environments

• cell membranes

• skin

• protects us on the outside & keeps the insides separate

Necessary Life Function: MOVEMENT (muscle contractions)

• of body parts (skeletal muscle)

• of substances (cardiac and smooth muscle)

Necessary Life Function: RESPONSIVENESS (respond to changes)

• ability to sense and respond to stimuli (how we adapt to external & internal changes)

• controlled by the nervous system

• reflexes (signals coming from the brain)

Necessary Life Function: DIGESTION (gives us nutrients)

• breakdown of ingested food

• absorption of simple molecules into blood

Necessary Life Function: METABOLISM

• all chemical reactions that occur in body cells

• CATabolism: break down large molecules into smaller parts (ate a lot of bread needs to break down ) big to small

• ANabolism: build up large molecules from smaller parts (cells to tissues to organs..) small to big

Necessary Life Function: EXCRETION

• removal of wastes from metabolism and digestion

• urea (biproduct of metabolism), carbon dioxide (exhale biproduct of cells working to make ATP), feces

Necessary Life Function: REPRODUCTION

• cell division for growth or repair

• production of offspring

Necessary Life Function: GROWTH

• increase in size of a body part or of organism

• hormones promote growth

organ system: INTEGUMENTARY SYSTEM

STRUCTURE

• External covering: skin

• Derivatives: sweat glands, oil glands hair and nails

FUNCTION

• protects underlying structures

• synthesizes vitamin D

• maintains body temperature (sweat glands- sweat cools us down)

organ system: MUSCULAR SYSTEM

STRUCTURE

• muscles

FUNCTION

• movement (contraction of the muscles)

• maintain posture

• produces heat (shivering- muscles rapidly contract to produce heat)

organ system: SKELETAL SYSTEM

STRUCTURE

• bones

• joints

• cartilage

• ligaments

FUNCTION

• protects organs (ex: ribcage protects heart and lungs)

• attachment sites for muscles

• (bones) formation of blood cells (white,red,etc)

• stores minerals - calcium (why bones look white)

organ system: NERVOUS SYSTEM

STRUCTURE

• brain

• spinal cord

• nerves

FUNCTION

• control center (hey its getting hot i need to send a message to the sweat glands to produce sweat to cool us down)

• respond to internal and external changes

organ system: CARDIOVASCULAR SYSTEM

STRUCTURE

• heart

• blood vessels

FUNCTION

• pumps blood (contract & relax to push blood through blood vessels)

• transports oxygen, nutrients, waste, carbon dioxide

organ system: RESPIRATORY SYSTEM

STRUCTURE

• nasal cavity

• pharynx, larynx

• trachea

• bronchi

• lungs

FUNCTION

• gas exchange

• oxygen delivered to blood (bringing oxygen in)

• carbon dioxide removed from blood

organ system: DIGESTIVE SYSTEM

STRUCTURE

• oral cavity

• esophagus

• stomach, small and large intestines, rectum and anus

• accessory organs- liver, gallbladder, salivary glands and pancreas

FUNCTION

• breaks down food into absorbable parts

• eliminates waste

organ system: URINARY (renal) SYSTEM

STRUCTURE

• kidneys

• ureters

• bladder

• urethra

FUNCTION

• eliminates nitrogenous waste

• regulates body water levels

• maintains blood electrolytes and acid-base balance

organ system: MALE REPRODUCTIVE SYSTEM

STRUCTURE

• scrotum, testes, ductus deferens, penis

• glands- prostate, seminal vesicles, bulbo - urethral

FUNCTION

• reproduce offspring

• produce sperm and testosterone

organ system: FEMALE REPRODUCTIVE SYSTEM

FUNCTION

• ovaries

• uterine (fallopian) tube

• uterus

• vagina

• mammary glands

FUNCTION

• reproduce offspring

• ovaries produce egg, estrogen, progesterone

• mammary glands produce milk

organ system: ENDOCRINE SYSTEM

STRUCTURE

• Glands - pineal (produces melatonin), pituitary, thyroid, parathyroid, thymus, adrenal (goes away into adulthood), pancreas, ovaries (produce estrogen & progesterone), testes (produce testosterone)

FUNCTION

• secrete hormones

• regulate growth and hormones

organ system: LYMPHATIC SYSTEM

STRUCTURE

• thymus gland

• lymphatic vessels, thoracic duct, lymph nodes

• red bone marrow and spleen (excessive red blood cells/ old blood cells go to recharge)

FUNCTION

• recaptures lost fluids from blood (lymphatic vessels)

• involved in immunity

Which 2 organ systems play a major role in maintaining homeostasis of the internal environment?

nervous system and reproductive system

Survival Needs: APPROPRIATE AMNTS (necessary for life)

too much or too little can be harmful and even inconsistent with life

Survival Needs: NUTRIENTS (the body’s fuel)

• chemicals for energy and cell building

• carbohydrates, fats, proteins, minerals, vitamins

Survival Needs: OXYGEN (breathing)

• required for the production of ATP (cells energy)

Survival Needs: WATER (chemical rxns need H2O to function)

• most abundant chemical in body

• provides the necessary environment for the bodies chemical reactions

• fluid base for secretions and excretions

• ex: saliva has water & chemical rxn’s to start the breakdown of food in the mouth

Survival Needs: NORMAL BODY TEMPERATURE (optimal body temp, where body functions well)

• 98.6 degrees Fahrenheit

• affects the rate of chemical reactions

• if body temperature falls below normal, chemical reactions will slow or even stop leading to loss of function or death

• if body temperatures rise above normal, chemical reactions will proceed too fast and their products (proteins) will break down leading to loss of function or death

Survival Needs: APPROPRIATE ATMOSPHERIC PRESSURE

• the force exerted on the body by the weight of air

• required for adequate breathing and gas exchange in lungs

• regions of high altitude & lower atmospheric pressure (mtns or really deep water), gas exchange will be slower, there will be less nutrients for metabolic activities

HOMEOSTASIS

• is the bodies ability to maintain an internal dynamic state of equilibrium, despite constant changes in the external environment

• involves continuous monitoring and regulation of all factors that can change (variables)

  • variables like body temperature or blood pressure

• three basic components of homeostatic control:

  • receptor (takes in sensory information)

  • control center (determines the “set point” and regulates the body’s response)

  • effector (carries out the body’s response)

    • response either reduces (negative feedback) or enhances stimulus (positive feedback)

FEEDBACK MECHANISMS

• interactions among the components of a homeostatic control system to maintain stable internal conditions

NEGATIVE FEEDBACK

• most feedback mechanisms in the body are negative feedback

• response reduces or shuts off original stimulus

  • variable changes in opposite direction of initial change

• examples

  • regulation of body temperature ( a nervous system mechanism)

  • regulation of blood glucose by insulin (an endocrine system mechanism)

• self-correcting loop that keeps the body's conditions stable- does the opposite of what is wrong

• ex: When you get too hot: Sensory receptors in your skin and brain detect the rise in temperature. Your brain's control center (the hypothalamus) signals effectors like sweat glands to produce sweat, which cools you as it evaporates. It also signals blood vessels in your skin to dilate (widen), allowing more blood to flow to the surface and release heat. This action brings your body temperature back down.

POSITIVE FEEDBACK

• response increases the original stimulus

• may exhibit a cascade or amplifying effect

• biological process that amplifies a change, pushing a system further away from its starting point. Instead of correcting a change, it makes the effect stronger and stronger, like a snowball rolling downhill. It's used for temporary processes that need to be completed quickly.

• ex: childbirth

  • Childbirth is the most famous example of positive feedback in the body.

  1. Stimulus: When the baby's head pushes on the cervix, it stretches the tissue.

  2. Response: The stretching sends signals to the brain, which releases the hormone oxytocin.

  3. Amplification: Oxytocin causes the uterus to contract more strongly. These stronger contractions push the baby further down, which stretches the cervix even more.

  4. The Loop Continues: This new stretching causes even more oxytocin to be released, leading to even stronger contractions. The process keeps building on itself until the baby is born. Once the baby is out, the stretching stops, and the loop is broken.

HOMEOSTATIC IMBALANCE OF FEEDBACK MECHANISMS

• disturbance of homeostasis

  • increases risk of disease

• contributes to changes associated with aging

  • control systems less efficient

• if negative feedback mechanisms overwhelmed

  • destructive positive feedback mechanisms may take over (heart failure)

POSITIVE & NEGATIVE FEEDBACK

The main difference between negative and positive feedback is their goal and effect on a system.

• Negative feedback works to stabilize a system by reversing a change to bring it back to a normal state. It's the most common type of feedback in the body and is essential for maintaining homeostasis.

• Positive feedback works to amplify a change, pushing the system further away from its normal state to complete a specific, often temporary, process. It's much less common in the body.

ANATOMICAL POSITION

• standard anatomical body position

  • body erect, upright

  • feet slightly apart

  • palms facing forward

    • thumbs point away from body

• always describe the body in anatomical position (opposite of your right and left)

Directional Terms: SUPERIOR (cranial)

• toward the head end or upper part of a structure or the body; above

• EX: the head is superior to the abdomen

Directional Terms: INFERIOR (caudal)

• away from the head end or toward the lower part of a structure or the body; below

• EX: the navel is inferior to the chin

Directional Terms: VENTRAL (anterior)

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

• EX: the breastbone is anterior to the spine

Directional Terms: DORSAL (posterior)

• toward or at the back of the body; behind

• EX: the heart is posterior to the breastbone

Directional Terms: MEDIAL

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

• EX: the heart is medial to the arm

• only reference to the torso region

Directional Terms: LATERAL

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

• EX: the arms are lateral to the chest

• only reference to the torso region

Directional Terms: INTERMEDIATE

• between a more medial and a more lateral structure

• EX: the collarbone is intermediate between the breastbone and shoulder

Directional Terms: PROXIMAL

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

• EX: the elbow is proximal to the wrist

• only reference to the limbs

Directional Terms: DISTAL

• farther from the origin of a body part or the point of attachment of a limb to the body of the trunk

• EX: the knee is distal to the thigh

• only reference to the limbs

Directional Terms: SUPERFICIAL (external)

• toward or at the body surface

• EX: the skin is superficial to the skeletal muscles

Directional Terms: DEEP (internal)

• away from the body surface; more internal

• EX: the lungs are deep to the skin

While performing a dissection, the students noticed that the veins were closer to the skin than the arteries. Therefore, the veins were __________ to the arteries

superficial

BODY PLANE

• flat surface along which body or structure may be cut for anatomical study

SECTIONS

• cuts or sections made along a body plane

3 MOST COMMON BODY PLANES

• lie at right angles to each other

• sagittal plane

• frontal (coronal) plane

• transverse (horizontal) plane

SAGITTAL PLANE

• divides body into right and left parts

• produces a sagittal section

• Midsagittal (median) plane

  • lies on midline

• Parasagittal plane

  • Not on midline

FRONTAL (coronal) PLANE

• divides body into anterior and posterior parts

• produces a frontal (coronal) section

TRANSVERSE (horizontal) PLANE

• divides body into superior and inferior parts

• produces a cross section

OBLIQUE SECTION

• result of cuts at angle other than 90 degrees to vertical plane

If a person had a toe amputated, the surgeon would make a ______ cut to amputate the toe.

transverse

TWO SETS OF INTERNAL BODY CAVATIES

• cavities are separate from each other so they don’t mix

• dorsal body cavity (cranial - head & vertebral - spine)

• ventral body cavity ( thoracic - chest & abdominopelvic - abdominal/ pelvic)

THORACIC CAVITY SUBDIVISIONS

• pleural cavities

  • each surrounds a lung

• mediastinum

  • contains pericardial cavity (heart)

  • surrounds thoracic organs

• pericardial cavity

  • encloses heart

ABDOMINOPELVIC CAVITY SUBDIVISIONS

• abdominal cavity

  • contain stomach, intestines, spleen, and liver

• pelvic cavity

  • contains urinary bladder, reproductive organs, and rectum

SEROUS MEMBRANE/ SEROSA

• thin, double- layered membranes

• layers separated by slit- like cavity filled with serous fluid

• fluid secreted by both layers of the membrane

• jelly like substance so organs don’t rub together and don’t hurt

PARIETAL SEROSA

• lines internal body cavity walls

• on the outer side layer

VISCERAL SEROSA

• covers internal organs (viscera)

• closer to organ

PERICARDIUM

• heart

PLEURAE

• lungs

PERITONEUM

abdominopelvic cavity

BODY CAVATIES EXPOSED TO ENVIRONMENT

• oral and digestive cavities

• nasal cavities

• orbital cavities

• middle ear cavities