Lecture 1 Flashcards
Define homeostasis
Condition: body’s internal environment remains relatively constant w/in limits
Conditions of homeostasis:
- Optimum [ ] gases, nutrients, ions, and water
- optimal temperature and pressure for health of cells.
Define stress:
Any stimulus that creates an imbalance in internal environment
Most abundant cation in extracellular?
Na+ =sodium
Most abundant cation intracellular:
K+, potassium
Most abundant anion in the extracellular:
Chloride; Cl-
Define feedback system:
Circular situation in which the information about the status of something is continually reported to a central control region.
- feedback
Most common. Response that reverses the direction of the initial condition; stabilizes the diminishing original response. Ex: Arterial BP to inhibit HTN by barorecptor sending inhibition signal to medulla.
+ feedback:
Response that intensifies initial condition. Destabilizing. ONLY healthy ex: cervix stretching causes stronger uterine contractions.
How do you calculate gain in a feedback system?
[Control system response - uncontrolled response] / ERROR
What is error when calculating gain?
Error is the amt. of uncorrected increase in the CONTROLLED system
Describe cell membrane w/ respect phospholipids and proteins.
“Unit membrane” has cholesterol inserted among the phospholipids. Proteins are asso. W/ the membrane. Hydrophobic tails of phospholipid and hydrophilic head groups.
What characteristic is necessary to pass across cell membrane?
Lipid soluble (hydrophobic) substances can readily pass
Peripheral proteins
Loosely attached to one surface or the other of membrane. Easily removed. Can be anchored by GPI-proteins.
Integral proteins:
Inserted in one side or pass al the way through and are exposed on either side of membrane.
Functions of plasma membrane:
Defines the intra/extracellular fluid composition. Filters, information exchange between the cell and environment; ends/exocytosis
Nucleus
Control center of the cell; houses the DNA of cell
Endoplasmic reticulum
Network of tubular flat vesicles composed of lipid bilayer connected w/ nuclear membrane. Substances formed in other parts of the cell are conducted to other areas of the cell through matrix of the ER. Ribosomes attach to ER (RER). Other portions of the ER are smooth (SER)-lipid metabolism
Ribosomes
can function to synthesize new proteins
Golgi
Closely r.t ER….4 or more layers of stacked layers of thin, flat, enclosed vesicles lying near one side of the nucleus. it is located on the side of the cell where substances are extruded. Transport molecules molecules from the ER fuse to w/ the Golgi these substances then become lysosomes , secretory vesicles , and other cytoplasmic elements
Mitochondria
Main function is houses cellular (aerobic) respiration.
Lysosomes
Intracellular digestive system by way of hydrolytic enzyme. Ex: glycogen to glucose
Peroxisomes
Similar to lysosomes but formed by self-replication (or budding from SER) contain OXIDASES [not hydrolases like lysosome] Important for alcohol digestion
Endosomes
Provides environment for sorting p/t entering lysosomes
With which function is clathrin asso. ?
Clathrin is asso. W/ endocytosis (pino/phagocytosis)—-form coated pits w/ or w/o receptors. Clathrin forms the inner pit or interior of Micelle that is created when taking a substance in.
Characteristics of lysosomes
Contains hydrolases [hydrolytic enzyme] at low pH for interior of cell digestive system.
How are secondary lysosomes made?
Primary lysosomes fuse w/ phagocytic vesicles to form secondary lysosomes
What happens to undigested material?
Left behind w/in a residual body will be eliminated via exocytosis
What organelles are asso. W/ protein synthesis?
Ribosomes, ER, and Golgi
RIBOSOME role in protein synthesis:
Proteins are synthesized on ribosomes
Proteins translated on RER are bound for:
Lysosomes or secretion
Proteins translated on free ribosomes are bound for
Cytoplasm, nucleus, mitochondria, or to other cell membranes
Glycolysis or Kreb’s cycle require O2?
Kreb’s. Glycolysis is anaerobic.
End products of glycolysis:
Pyruvate X 2 [pyruvic acid]
End products of Kreb’s:
CO2 and water
Protein Intracellular trafficking from RER
Transport vesicles bud off ER and head to Golgi
Golgi further modifies protein.
Protein is then sent as secretory vesicles out of cell.
Or proteins can go to lysosome from RER
Types of locomotion
Ameboid movement, cilia and flagella, and microtubules
What uses ameboid movement in cell?
Macrophage and some other leukocytes
Differ Cilia and flagella
Flagella moves the cell. Cilia moves material from cell while not moving.
How are microtubules used for locomotion
Provide tracks on which motor molecules can move cargo
