Human Anatomy Chapter 4

Microfilaments

- contractile elements of the cytoskeleton

Nucleus

- control center of the cell - necessary for cell division & cell life - contains DNA

Chromosomes

- has a centromere

Endoplasmic Reticulum

- membranous system of tubules

Although cells have differences that reflect their specific functions in the body, what functions do they have in common?

- metabolize - reproduce - grow (increase mass) - respond to stimulus - move - maintain their boundaries - digest nutrients, & dispose of waste

Cell

the structural & functional unit of all living things, a complex entity

Cell Division

MITOSIS: - process of cell division for eukaryotic cells found in multicellular organisms - all cells come from existing cells & mitosis is how most cells divide - the only eukaryotic cells which do NOT divide by mitosis are sex cells aka gametes aka sperm & egg cells

True/False. The end product of mitosis is four genetically identical daughter nuclei.

False.

DNA replication occurs during:

interphase.

Organelle

metabolic machinery of the cell, "small organs"

Because these organelles are responsible for providing the most of the ATP the cell needs, they are often referred to as the "powerhouses" of the cell. They are often the:

mitochondria.

How many stages of mitosis are there?

6.

All animal cells have a cell wall.

False

Squamous Epithelium

- thin, flat, smooth surface, fit close together for layering

When a cell is not dividing, the DNA is loosely spread throughout the nucleus in a threadlike form called

chromatin.

Proteins are assembled on these organelles

ribosomes.

Smooth ER

-without ribosomes - lipid & steroid synthesis & drug detoxification

Chromatin

- threadlike structures in the nucleus - contain genetic material (DNA) - loosely dispersed genetic material within the nucleus that is NOT dividing

Centrioles

- two rod-shaped bodies near the nucleus - associated with the formation of the mitotic spindles

Rough ER

- with ribosomes= proteins, phospholipids, & cholesterol

What is the significance of the red blood cell being anucleate (without nucleus)? Did it ever have a nucleus? When?

- Limited life span - Doesn't reproduce - No nucleus= no new protein manufactured - Red blood cell has a nucleus before its released into the bloodstream

Interphase

- NOT reproducing - longer phase - growing & carrying out its normal stuff

The smallest diameter

- Red blood cells

The longest diameter

- Smooth muscle cell

Ribosomes

- attached to membrane systems or scattered in the cytoplasm - site of protein synthesis - densely stain - contain RNA & protein - float free or attach to rough ER

Red Blood Cells

- biconcave, flexibility, fit in the capillaries, bend

Lysosomes

- contains digestive enzymes of many varieties; "suicide sac" of the cell

Nuclear Envelope

- double layered porous membrane around the nucleus (the pores allow passage of RNA & protein)

Smooth Muscle

- long, skinny fibers, aid in muscle contraction/relaxation

Golgi Apparatus

- membranous system consisting of flattened sacs & vesicles; package proteins for export - stacked sacs with bulbous ends that package lysosomes or incorporate into plasma membrane

Mitochondria

- rod shaped - "powerhouses" of the cell - double membrane wall & produce ATP by citric acid cycle/oxidative phosphorylation

Plasma Membrane

- selective permeable - external boundary of the cell - regulates flow of materials into & out of the cell - proteins & glycoproteins - composed of phospholipids & globular proteins - bilayer with hydrophilic & hydrophobic layers - passive transport by concentration & pressure - active transport= requires energy= ATP - resting potential= essential to neurons, muscle cells (cardiac) ***protective barrier AND actively controls what goes into & out of the cell

Peroxisomes

- site of free-radical detoxification

Inclusions

- stored glycogen granules, crystals, pigments, & so on

During ________ the cell grows & performs its usual activities.

interphase

The plasma membrane not only provides a protective boundary for the cell but also determines which substances enter or exit the cell. We call this characteristic:

selective permeability.

Mircovilli

- slender extensions of the plasma membrane that increase its surface area

Nucleolus

- small round bodies that have RNA in them - dense, darkly staining nuclear body; packaging site of ribosome's

Sperm

- tail, moves sperm around to conceive