Transcript Biology 211 Anatomy & Physiology I

Biology 211
Anatomy & Physiology I
Cells
Recall:
SYSTEMS are composed of one or more organs,
all serving a common function
ORGANS are composed of one or more types
of tissues, all serving a common function
TISSUES are composed of one or more types
of cells and their products, all serving a
common function
CELLS are composed of different types of
organelles, all serving a common function
ORGANELLES are composed of different types
of molecules, all serving a common function
All cells in the human body share some important
characteristics:
-
Obtain nutrients from surrounding extracellular
matrix and secrete waste products into it.
- Use oxygen to metabolize fuel molecules
- Produce complex molecules from simpler precursers,
either for their own use or for export AND break
complex molecules back down into smaller ones
- Interact with other cells
- Reproduce themselves (this characteristic is lost in
some cells and retained in others)
Cells:
- Highly organized; composed of organelles and cytoplasm
- Arise from prexisting cells
Some exist as stem cells to replace more specialized ones
- In human, all eukaryotic: nuclei and other organelles
surrounded by membranes
- Some = highly specialized & can perform only one function
Others = relatively unspecialized with many functions
Cells:
Size: Highly variable
Average =
Range =
diameter
(sperm)
(oocyte)
Skeletal muscle cells may be
Nerve cells may be
Cells:
Shape: Highly variable:
Independent Study:
Chapter 3 of your Saladin
text (4th ed) discusses the
organelles of most cells.
You should understand the
basic structure and function
of each of the following:
Nucleus
Ribosomes
You should also understand the
Endoplasmic reticulum
basic structure and function of
Golgi complex
cilia and flagella
Mitochondria
Lysosomes
Peroxisomes
You will be responsible
Vesicles
for these on exams
Cytoskeleton
Plasma Membrane:
Also called "plasmalemma"
May have special names in specific types of cells
e.g. "sarcolemma" in muscle cells,
"neurolemma" in nerve cells
- Keeps inside in and outside out
while
- Contolling movement of ions/molecules into and out of cell
- Interacts with other cells and with extracellular materials
around cell
- Allows cell to recognize and respond to chemical signals
Plasma Membrane:
Basic structure = double layer of phospholipids with proteins
and cholesterol embedded within it
Plasma Membrane:
Regulates movement of ions and molecules into and out of
the cell, but highly selective
- Freely permeable to some molecules (e.g. oxygen)
- Partially permeable to others (e.g. glucose)
- Totally nonpermeable to some (e.g. glycogen)
Facilitates the uptake of ions/molecules needed by the cell
(sugars, fatty acids, amino acids, oxygen, hormones, etc)
Facilitates the release of waste products (carbon dioxide,
lactic acid, etc) and secretory products (hormones,
proteins, etc.)
Plasma Membrane:
This regulated movement is due to:
a)
b)
c)
Plasma Membrane:
Has specialized junctions for cell-to-cell attachment and/or
communication
1.
: Protein molecules in plasma
membranes of two adjacent cells form bonds; hold cells
strongly together and prevent materials from passing
between them
Plasma Membrane:
Has specialized junctions for cell-to-cell attachment and/or
communication
2.
: Protein molecules in plasma
membranes of two adjacent cells form bonds in isolated
spots; hold cells strongly together
Plasma Membrane:
Has specialized junctions for cell-to-cell attachment and/or
communication
3.
: Protein molecules in plasma
membranes of two adjacent cells form channels between
them; allow molecules to flow from cell to cell
Movement of Materials Across Plasma Membrane:
Thousands of different materials are actively crossing the
plasma membrane, both into and out of the cell:
e.g. Water
Nutrients like amino acids, monosaccharides,
fatty acids, nucleotides, vitamins
Gases like oxygen, carbon dioxide
Waste products like lactic acid, urea, bilirubin
Ions (electrolytes) like sodium, potassium, magnesium,
iron, calcium, chloride, phosphate, sulfate
Hormones like insulin, estrogens, growth hormone
Neurotransmitters
Secretory proteins and lipoproteins
Debris which phagocytic cells ingest
(many others)
Movement of Materials Across Plasma Membrane:
Thousands of different materials are actively crossing the
plasma membrane, both into and out of the cell:
This is not a random process! Each cell has a variety of
different processes to regulate this exchange so that
The right materials cross the membrane
In the right concentrations
At the right time
In the right direction
etc.
Movement of Materials Across Plasma Membrane:
More Independent Study:
Saladin text discusses various types of membrane transport.
Be sure you understand, in moderate detail, how each of
the following occur and what it accomplishes:
- Filtration
- Simple diffusion, including osmosis and the effects of
osmolarity and tonicity
- Carrier mediated transport, including facilitated diffusion
and active transport
- Vesicular transport, including endocytosis, exocytosis,
phagocytosis, pinocytosis,
You will be
transcytosis, and receptorresponsible for
mediated endocytosis
these on exams
Let's move on to tissues