The Cellular and Tissue Levels of Organization

Question 1

Cells

Answer 1

• Smallest units that perform all vital physiological functions
• Each cells maintains Homeostasis at the cellular level
• Homeostasis at higher levels reflects combines, coordinated action of ma cells

Question 2

Cells of Interest in the Human Body

Answer 2

• Eukaryotic cells
  
  • 10-100 micrometers
• Prokaryotic cells-bacteria
  
  • 1-10 micrometers
• Parasites-eukaryotes
  
  • single cells-Protista
  • multicellular - fungi, insects, worms, etc…
• viruses not cells

Question 3

Describe a typical human body cell

Answer 3

• Surrounded by an extracellular fluid, which is the fluid of the tissue
• cell membrane forms the outer membrane
  
  • plasma membrane or plasma lemma
• Cytoplasm
  
  • Cytosol and organelles
• Nucleus

Question 4

What are the cell membrane functions.

Answer 4

• Physical Isolation - Extracellular and intracellular fluid composition differ (Cellular Homeostasis)
• Regulation of exchange with the environment - Semi permeable
  
  • Controls entry of ions, nutrients
  • controls exit of water, release of secretions
• Sensitivity and recognition
• Structural Support

Question 5

Cell Membrane

Answer 5

• Phospholipid Bilayer
  
  • Hydrophilic phosphate group on surface
  • Hydrophobic fatty acid tails inside
• Fluid Mosaic Membrane
  
  • Membrane
  • cholesterol
• Glycocalyx on extracellular surface
  
  • Sugar groups attached to membrane lipids and membrane proteins

Question 6

Functions of membrane proteins and carbohydrates

Answer 6

• Transport Proteins
• Chanel Proteins
• Anchoring
• Cell identity - genetically located recognition factors
• Receptors

Question 7

What is the dynamic membrane of the cell

Answer 7

• Golgi Apparatus
• Endoplasmic Reticulum
  
  • Sooth ER
  • Rough Er
• Vesicles
• Endocytosis

Question 8

Endoplasmic Reticulum (Smooth and Rough)

Answer 8

Smooth Endoplasmic Reticulum:

Synthesis of lipids and carbohydrates

Rough Endoplasmic Reticulum:

Synthesis of Proteins

Question 9

Golgi Apparatus

Answer 9

Packages and process products of the RER and SER

Question 10

Digestive Organelles:

Proteasomes

Answer 10

Digest damaged and abnormal proteins

Question 11

• *Digestive Organelles:**
• *Peroxisomes**

Answer 11

Enzymatic breakdown of lipids and toxins

Question 12

• *Digestive Organelles:**
• *Lysosomes**

Answer 12

Lysosomes-Vesicles with multiple types of digestive enzymes

• Digest organelles, engulfed materials for recycling
• Responsible for the lycing of injured cells

Question 13

What does the Mitochondria do?

Answer 13

• Responsible for ATP production through aerobic respiration of small organic molecules
• site of cellular respiration - uses O2 and creates CO2 as waste
• Large number in cytoplasm of metabolically active cells that carry out aerobic metabolism

Question 14

What does the nucleus do?

Answer 14

• 23 pairs of chromosomes storing the genetic information of the human body
• sequence of nucleotides in DNA is transcribed creating mRNA with corresponding nucleotide sequence
• mRNA exits nucleus, carrying information that is read by ribosomes to synthesize proteins

Question 15

Cell Cycle and Differentiation

Answer 15

• All cells of a human body derive from cell divisions starting with a fertilized egg
  
  • All somatic cells (non sex cells) contain the same genes
• Differentiation results from inactivation or activation of particular genes
  
  • Early embryonic cells (undifferentiated) can form any type of cell
  • Differentiation produces populations of specialized cells with limited capabilities

Question 16

Differentiated Cells

Answer 16

• Adult stem cells
  
  • Retain ability to divide and differentiate into one or a few types of cells
• Tissues
  
  • Collections of specialized cells and cell products that preform a specific function
  • Adult stem cells (germinative cells) present in tissues for growth and repair

Question 17

What are the four tissue types?

Answer 17

• Neural Tissue
• Muscle Tissue
• Epithelial Tissue
• Connective tissue
• Most organs contain all 4 types

Question 18

Neural Tissue

Answer 18

• Nerve cells and support cells of brain, spinal cord, nerves, and sensory organs
• conveys information from one aera to another in form of electrical signals
  
  • Receives stimuli, creates electrical signal
  • integrates and interprets electrical signals
  • controls effectors such as skeletal, smooth, and cardiac muscle

Question 19

Muscle Tissues

Answer 19

• Skeletal Muscle
• Cardiac Muscle
• Smooth Muscle

Question 20

What does Connective Tissue do?

Answer 20

• Provides structural Framework for body
• Transports Materials within body
• Protects and supports organs
• Interconnects and supports other tissues
• Stores energy reserves
• Defense against invading microorganisms

Question 21

Connective Tissue

Answer 21

• Specialized Cells embedded in matrix of extracellular fibers and fluid
• Connective tissue Proper
  
  • Fibroblasts in matric of collagen, reticular, and elastic fibers
  • Adipose, Areolar, Tendons, and Ligaments
• Fluid Connective Tissue:
  
  • Blood cells in fluid matrix
• Supportive Connective Tissue
  
  • Cartilage and Bone

Question 22

Epithelial Tissue

Answer 22

• Covers external surfaces
• Lines internal surfaces
• Forms glands
• Has polarity
  
  • Apical end of cells on surface
  • Basal end of cells attached via basal lamina to underlying connective tissue

Question 23

Epithelial Specialization

Answer 23

• Cilia move materials across the surface
• Microvilli increase surface aera for absorption
• Intercellular connections:
  
  • Tight junctions
  • Gap Junctions
  • Desmosomes

Question 24

Glandular Epithelia

Answer 24

• Exocrine Glands:
  
  • Secrete through ducts onto the surface of epithelium
• Endocrine Glands:
  
  • Release Hormones into the surrounding interstitial tissue

Question 25

Merocrine Secretions

Answer 25

• Merocrine:
  
  • product released through exocytosis
• Examples:
  
  • Salivary glands

Question 26

Apocrine Secretions

Answer 26

• Apocrine Secretion:
  
  • Secretion involving the loss of both product and cytoplasm
• Example:
  
  • Mammary Glands

Question 27

Holocrine Secretion

Answer 27

• Holocrine Secretion:
  
  • Secretion that destroys the entire cell
• Examples:
  
  • Sebaceous sweat gland