Physiology Chapter 1

Cell

Fundamental structural and functional unit of life capable of carrying out basic survival processes

Tissue

a group of cells with simillar structure and function. There are 4 types

1. Muscle Tissue

a. Skeletal

b. cardiac

c. smooth

Specialized for contraction and generating force to produce movement in the body. There are 3 types (skeletal, cardiac, smooth)

1a. Skeletal muscle tissue

Moves bones, causes locomotion

1b. Cardiac muscle tissue

contracts, moved blood through force

1c. smooth muscle tissue

within all hollow organs of the body.

2. Nervous Tissue

specialized for initiating and transmitting electrical signals to communicate across the body

3. Epithelial tissue

Specialized for exchanging materials between the cell and its environment, lines outside of all organs and the whole body, epithelial sheets vs secretory glands.

4. Connective tissue

specialized for connecting, supporting, and anchoring body parts.

Homeostasis

the maintenance of a relatively stable environment inside the body

Endocrine glands

ductless glands derived from epithelial tissue that secrete hormones directly into the bloodstream to regulate target organs extrinsically

Exocrine glands

glands derived from epithelial tissue that secrete products through ducts onto an external surface or into an internal cavity communicating with the outside

Organ

Structural unit composed of two or more types of primary tissues that are organized together to perform specific functions (e.g., the stomach)

Organ system

A collection of organs that interact and coordinate related functions to accomplish a broad survival goal (e.g., the digestive system)

Integration

the process by which different organ systems coordinate their operations to maintain whole body balance

Intracellular fluid (ICF)

the fluid contained inside ALL body cells

Extracellular fluid (ECF)

The fluid OUTSIDE the cells. ECF acts as the body’s internal environment, where cells directly make life-sustaining exchanges. Has a plasma component and an interstitial fluid component.

Plasma

liquid portion of blood (intravascular component of ECF)

Interstitial fluid

the fluid surrounding a bathing cells outside of blood vessels

Dynamic steady state (homeostasis)

a condition where a variable (like body temp or blood sugar level) continuously fluctuates around a central set point, but energy is actively expended to keep those fluctuations bounded

Compensatory physiological response

a bodily reaction triggered to counteract a disturbance and restore the internal environment to its optimal set point

Intrinsic control (Local)

inherent, self-serving control mechanisms that originate within a specific organ or tissue (e.g., vasodilation for better O2 exchange when muscles are working)

extrinsic control (systemic)

control mechanisms originating outside an organ, governed by the nervous system or the endocrine system to coordinate whole body homeostasis (sensory neurons feel cold, tells brain, brain sends signals to speed up heart rate to keep body warm. heart didn’t do that on its own, it had to be told)

Neuronal compensatory response

happens fast, doesn’t last long

Hormonal compensatory response

takes longer to start but response lasts longer

Negative feedback system

a primary homeostatic control mechanism where a change in a monitored variable triggers a response that drives the variable in the opposite direction of the initial change, opposing the shift. (shivering when cold to bring temp back up)

Positive feedback system

A control mechanism where a change in a variable triggers a response that drives the variable in the same direction as the initial shift, amplifying the change until an explosive endpoint is reached (birth contractions)

Key ECF variables maintained by homeostasis

nutrient concentrations, O2/CO2, waste product levels, pH balance, water/salt/electrolytes, volume and pressure, temperature