Chapter 32 Flashcards
Homeostasis
A condition in which the internal environment of the body remains relatively constant despite changes in the external environment.
Why is homeostasis so important?
Failure to maintain homeostasis results in imbalances, later causing sickness, disease, and death.
Lowest heart rate occurs at what time of the day?
Around 3am because we are asleep, so we have slower heartbeat.
Morning hypertension occurs around what time?
Around 7am because of the rapid rise in blood pressure.
What time of the day is the highest risk of cardiac arrest?
Around 10am because of dehydration and the constriction of blood vessels.
What time of the day does a person have the fastest reaction time?
Around 3pm.
What time of the day does a person have the greatest muscle strength?
Around 7pm.
What time of the day does the secretion of melatonin begin?
Around 9pm. Pineal melatonin secretion occurs during the nighttime. Melatonin secretion involves the regulation of the human circadian core body temperature.
Levels of biological organization:
Cell- Tissue- Organ- Organ System- Organism
What function does the cell membrane perform to maintain homeostasis?
Cell membranes help organisms maintain homeostasis by transporting or moving material in and out of the cell.
What methods of transport are responsible for exchange across the cell membrane?
Passive, active, and bulk transports
How does the size of a cell effect exchanges made by the cell to it’s environment?
The size of a cell directly affects how it exchanges with its environment. Exchange is effective over very short distances. A large cell is limited by the distance materials must travel from the center of the cell to its surface, which ultimately causes the cell to not satisfy metabolic demands.
How does exchange work in single cell organisms?
Exchange occurs by simple diffusion. Exchange is simple because the organism is small in size and has direct contact with external environment (lives in water).
How does exchange work in multicellular organisms?
Exchange occurs by simple diffusion. Each cell has its own plasma membrane, so each layer of cells is in direct contact with the external environment.
How does exchange work in complex multicellular organisms?
Cells are embedded inside the organism and therefore isolated from direct contact with the external environment. Exchange surfaces include digestive, respiratory, and circulatory systems, meaning large organisms need more specialized transport systems or diffusion would be too slow.
How can cells with no direct contact with the external environment make exchanges?
Those needs are met by the internal environment, namely the extracellular fluid which allows for the movement of material into and out of the cells.
Passive Transport
Does not use the cell’s energy in brining materials in and out of the cell.
Active Transport
Does use the cell’s energy in bringing materials in and out of the cell.
Bulk Transport
Involves the cell making membrane bound vesicles to bring materials in and out the cell.
What two components make up the extracellular fluid?
Plasma and interstitial fluid.
Plasma
Fluid portion of blood.
Interstitial fluid
Fluid that surrounds the cells, sometimes referred to as tissue fluid.
What is the role of extracellular fluid?
Connects all cells to the external environment so no matter where a cell is located it can make the exchanges essential to life.
What level of biological organization enables the exchanges between the internal and external environments?
Organ systems
What is the primary function of the cell membrane?
It allows certain materials to enter and exit the cell.
Interstitial fluid and plasma are both considered _______ fluid and make up the ________ of the body.
intracellular; internal environment
Interstitial fluid is…
the route for the exchange of materials between blood and body cells.
Cell is…
the smallest unit of life
Tissue is…
an organized group of cells, working together as a functional unit
What are the 4 types of tissues?
Epithelial, connective, muscle, nervous
Where is epithelial tissue located?
Cover the surface of the body and lines the cavities within the body.
What are the two surfaces of connective tissue?
Apical surface is the free side that faces away from other tissues.
Basolateral surface is the secured side which is tightly bound to neighboring cells.
Epithelial tissues are classified according to…
Shape (squamous, cubodial, columnar) and Layers (simple or stratified)
Function of connective tissue is…
mainly binds and supports other tissues
Loose connective tissue:
binds epithelial cells to underlying tissues and holds organs in place
Dense connective tissue:
has more collagen fibers. Includes tendon (attaches muscle to bone) and ligament (attaches bone to bone).
Blood:
is composed of blood cells and cell fragments in the blood plasma. (classified as a tissue, does not connect but transports)
Cartilage:
is a strong and flexible support material
Adipose tissue:
stores fat for insulation and fuel
Hyaline cartilage:
flexible and resilient and not easily compressed, within joints and nose
Elastic cartilage:
is flexible and bendable yet rigid, ear and larynx
Fibrocartilage:
is sturdy, tough and inflexible, knee
What is the function of muscle tissue?
It is responsible for all types of body movement.
What do muscles consist of?
They consist of filaments of the proteins actin and myosin, which enable muscles to contract.
What are the three types of muscle tissue?
Skeletal, Cardiac, and Smooth
Smooth Muscle
- No striations, spindle shaped cells
- Single nucleus in each cell
- Found in the walls of blood vessels and visceral organs
- Involuntary contractions
Skeletal Muscle
- Striated appearance
- Cells are multinucleated
- Attached to bone by tendons
- Voluntary contractions
Cardiac Muscle
- Striated and branched appearance
- Single nucleus
- Contain gap junctions
- Involuntary contractions