Intro to Physiology Flashcards
Hierarchy of Body Organization
6
What are Cells?
- The basic structural and functional unit of all living organisms
- The activity of an organism depends on the collective activities of its cells
- Primarily made up of C, H, N and O
What are common characteristics of a cell?
- Plasma membrane
- Cytoplasm
- Nucleus (RBC exception)
What is the Cell Membrane comprised of?
Made up of Phospholipids that are amphiphatic
Have a Hydrophobic Tail (Non-polar) and Hydrophilic Head (Polar). Membrane is “Semi-Permeable”
What is Simple Diffusion?
Lipid-Soluble Solutes can pass straight through the membrane from High to Low concentration
How does Water pass through the membrane?
Water goes from Low to High Concentration through channel proteins called aquaporins in a process called Osmosis
What is Facilitated Diffusion?
Small Lipid Insoluble membranes pass through a Channel protein (mostly ions)
How do larger Molecules like Glucose pass through the Membrane?
Facilated Diffusion via specific protein carriers that allow passage of a specific molecule by changing shape once a substrate binds
When is ATP required in membrane transport?
Only in active Membrane Transport
What is Endocytosis?
- Engulfing (taking up) of substances in the extracellular environment by enclosing them in a vesicle
- Vesicle travels in the cytoplasm where it typically attaches to a lysosomes and spills its contents
What is Exocytosis?
- Ejection(secretion) of substances (hormones, cellular debris, waste etc.) from the cell
- The product to be released is packaged into a vesicle which fuses to the cell membrane and the contents are released to the exterior of the cell
What is Cytoplasm?
Outside the nucleus and inside the cell membrane
- Where most cellular activity takes place, Contains:
i. Cytosol – fluid that suspends other elements, largely composed of water
ii. Inclusions – commonly stored nutrient products that float in the cytosol (i.e., lipid droplets, glycogen granules)
iii. Organelles – the metabolic machinery of the cell, each organelle has a specific function
Mitochondria
- Double membraned organelle
- Supply most of the ATP used for cellular activity
- Highly metabolic cells (i.e., liver and skeletal muscle) have more mitochondria
- Can replicate by pinching in half (found more in athletes)
Ribosomes
- Made of proteins and rRNA (ribosomal RNA)
- The site of protein synthesis
- Free floating or bound to rough endoplasmic reticulum
The Cytoskeleton
- Not an organelle
- Elaborate network of protein structures
- Determines the cell shape, supports organelles, provides machinery for intracellular transport
- Comprised of microfilaments, intermediate filaments and microtubules
Microfilaments
Intermediate Filaments
Microtubules
The Nucleus
*not in RBC
- The “control center” of the cell
- Necessary for cell replication
- Contains DNA, which has genes, that codes for proteins
Nuclear Envelope & Nucleolus
Nuclear Envelope
- Double membraned barrier
Nucleolus
- Assembly of ribosomes (which eventually move to cytoplasm)
Chromatin
- Scattered throughout the nucleus
- Contains genetic material
Not all cells are alike…
What are Tissue?
Tissues: groups of cells that are similar in structure and function
What are the Four Primary Tissue Types in the Human Body?
- Epithelial
- Connective
- Muscle
- Nervous
Epithelial Tissue (Epithelium)
Protects the body/organs
- Skin epithelium protects against bacteria and chemical damage
- Respiratory tract epithelium has cilia that protects against dust and debris
Filters
- Renal epithelium filters out molecules of different sizes
Selectively secretes/absorbs
- Glandular epithelium secretes sweat, digestive enzymes, hormones etc.
- Digestive epithelium absorb nutrients from food).
Enables sensation
- Epithelium supports sensory neurons located in the skin, nose, mouth, eyes, and ears
How do we Classify Epithelium?
CELL ARRANGEMENT + SHAPE OF CELL
Cell Arrangement -> simple (one layer of cells), stratified (more
than one later of cells) or pseudostratified (false impression of
stratification)
Shape of Cell -> squamous, cuboidal, columnar or transitional
How does structure dictate function?
What is the Apical Membrane?
Apical Surface: exposed to the body’s exterior or to the cavity of an internal organ. Can be smooth, or have cell surface modifications, such as microvilli or cilia
What is the Basal Membrane?
Basal Surface: the anchored surface of epithelium, rests on a basement membrane
What is the Basement Membrane?
Basement Membrane: a structureless material secreted by both the epithelial cells and the connective tissue cells deep to the epithelium, the “glue” holding the epithelium in place
Membrane Examples
What is the Main function of Alveoli? What type of epithelial cell is it to facilitate this?
Gas exchange simple squamous
Cilia
on epithelial used for filtering.
Line the Trachea
Examples and Roles of Connective Tissue?
Cell Types (not inclusive)
- Osteocytes
- Chondrocyte
- Fibroblast/FAP Cells
- Adipocytes
- Erythrocytes
Primary Roles:
1. Protect
2. Bind/support
3. Insulate
4. Transport
Roles of Connective Tissues?
-
Osteocytes:
- Primary Role: Protect, Bind/support
-
Chondrocyte:
- Primary Role: Bind/support
-
Fibroblast/FAP Cells:
- Primary Role: Protects, Bind/support, Transports
-
Adipocytes:
- Primary Role: Insulate
-
Erythrocytes:
- Primary Role: Transport
What are Osteocytes?
Osteocytes are mature bone cells that maintain bone tissue by regulating mineral content and responding to mechanical stresses.
Bone
What are Chondrocyte?
Chondrocytes are specialized cells found in cartilage that produce and maintain the extracellular matrix, essential for the structural integrity and flexibility of this connective tissue.
What are Fibroblast/FAP cells?
Fibroblast/FAP cells are connective tissue cells crucial for synthesizing and maintaining the structural framework of tissues by producing extracellular matrix components.
Produce Collagen, found in skin, hair, bone, b/w cells and muscles
What are Adipocytes?
Adipocytes are cells primarily responsible for storing energy in the form of triglycerides as fat droplets, playing a key role in energy metabolism and insulation.
What are Erethrocytes?
RBC
What are Muscle Tissue?
- Specialized to contract (shorten) and create the force required for movement
- Excitable – respond to nervous stimulation
What are 3 Types of Skeletal Muscle?
- Skeletal
- Cardiac
- Smooth
Make into Seperate Cards*
- Skeletal (long, cylindrical)
- Cardiac (intercelated discs)
- Smooth (no striations)
What is Nervous Tissue?
Cell Type: Neuron
- Excitable (responds to stimulation)
- Receives and sends electrochemical impulses
- The cytoplasm is drawn out into long processes
(allowing a single neuron to send signals to
distant body parts) - Connection between two neurons à synapse
What is the Soma of the Neuron?
Soma: the cell body of a neuron
What are Dendrites of Neurons?
hundreds
Dendrites: long processes extending from the soma
- Receives incoming information and transmits to the soma
- Each neuron has hundreds of dendrites
What are the Axons of the Neuron?
only one
Axon: a long process extending from the soma
- Relays outgoing signals to target cells
- Begins at the axon hillock and ends at the axon terminal
What is the Myelin of the Neuron?
Myelin: an insulating sheath that forms over some neurons
- Speeds up electrical transmission down the axon
The Neuron
What is Neuroglia?
(non-excitable)
- Insulate, support and and protect neurons
- Non-neuronal cells
- Cannot transmit electrical impulses
Neuroglia
What are Astrocytes?
Neuroglia
What are Microglia?
(phagocytes)
Neuroglia
What are Ependymal Cells?
What are Oligodendrocytes?
What are Nodes of Ranvier?
- Produced by oligodendrocytes (CNS) and Schwann Cells (PNS)
- “Gaps” in the myelin sheath called Nodes of Ranvier, allow for saltatory conduction
- Protects nerve fibres and increases the speed of nerve impulse transmission
What type of Tissue do Skeletal Muscles Have?
What about the Heart?
All 4 for both
