(3) Homeostasis & Body planes

Homeostasis

• relatively constantstate mainted by the body.

• Maintains a range of nutrients ( H2O, sodium, glucose, etc.) In the bloodstream

• organic state of equilibrium

• Homeo= sameness, stasis = standing still

Homeostatic control mechanisms

• how the body changes the internal environment

• To maintain homeostasis= cells must be in an environment that allows them to function properly with changing external conditions.

• Organs and system must work to maintain homeostasis

Sensor mechanism

• Act as sensors →if something changes in a normal set point range on homeostasis

• sending through nerves in the brain.

Effector mechanism

• provide the response desired by the integrator → in temp: Muscle shiver : Up temp. & Sweat: Lowers temp.

• influences the change of the values of variables

• can be + or - value change.

Set point

• normal range the body tries to stay within

• the body can change the set point

• Stages Systolic

Normal 80-120

Pre-hyper tension 121- 139

Stage 1 HBP 140-159

Stage 2 HBP 160- Higher

Feedback systems

• through nervous impulses & chemical messengers/ hormones

• the body is continually monitored, evaluated, changed, remonitored & re evualated

• Consists of 4 main components: Sensor mechanism/ Receptor, integrator/ control center, effector mechanism, and feedback

Integrator/ control center

• many times it is in the parts of the brain, it checks the values of the variables against the allowable set point range.

• Receives the signal and analyzes it.

Feedback

• new ariable values lie within the set point range

Feedback control loops

• process of the body adjusting to a change

• Can be positive or negative

• Example: Glucose level, stress, body tep.

• Negative & positive - differences is their response to the change

Negative feedback control loops

• Reverses a change in controlled situation

• More common

• Helps the body maintain homeostasis

Positive feedback control loops

• does not help maintain homeostasis

• strengthens a change in one of the body’s controlled condition

• amplifies the change

• can be a normal reaction, but could be harmful when metabolic rates elevates → For example: Shivering & sweating at the same time

• Can be beneficial in the body

Body plane

• cut along the surface

Parasagittal plane

• an imaginary vertical line that runs parallel to the midsagittal plane

Sagittal plane

• run top to bottom

• run front to back

• divide the body into right and left sections

Midsagittal plane

• midline of the body & divides into equal halves

Coronal / Frontal plane

• run side to side

• run top to bottom

• divide the body into anterior and posterior

Transverse plane

• run side to side

• run front to back

• divide the body into upper & lower section

• sometimes called “ Horizontal planes”

Oblique planes

• run front to back

• run side to side

• run top to bottom

Body positions

• a standard position

• wherein the body is erect with feet parallel, arms at sides, palms facing forward