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Nutrition: A Biology Perspective. Will Brown Lecture 2. Objectives and Content. Objective: Define the nutritional needs of a human being from a physiological and biological point of view Contents Cells and cell structure Cellular metabolism and respiration Tissues and organ systems. - PowerPoint PPT Presentation
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Nutrition: A Biology Perspective
Will BrownLecture 2
Objectives and Content
• Objective: Define the nutritional needs of a human being from a physiological and biological point of view
• Contents– Cells and cell structure– Cellular metabolism and respiration– Tissues and organ systems
Anatomy and Physiology
• What is the difference between anatomy and physiology?
• Anatomy – The structural elements that comprise an organism– Includes placement of various organs and organ
systems in relation to each other• Physiology – The function of the various organs
and organ systems• Remember that Structure dictates Function
Cells
• The most basic anatomical (structural) and physiological (functional) component of an organism
• Organelles – “Little organs” – Specialized structures and compartments within a
cell• There are 8 organelles that we are interested
in for this class
Plasma (Cell) Membrane• Outer most layer of animal cells – technically not an
organelle• Functions– Regulate transport into and out of the cell– Cell-to-cell communication– Defines what is outside and what is inside
• Composition– Phospholipid bilayer– Cholesterol– Proteins– Carbohydrates
Dhatfield; 2008
Cytoplasm
• Also, technically not an organelle• The inner fluid of the cell• Anaerobic metabolism can occur via chemical
processes– Sole source of energy production for red blood
cells
Mitochondria
• The “power plant” of the cell• Responsible for most of the energy production • Aerobic metabolism• Other things of note (but not test material)– Have their own genome; which is closer to
bacteria than to human– All of your mitochondria are maternally derived• There are specific metabolic diseases that are
maternally inherited
Nucleus
• All cells, expect RBC, have a nucleus. Some cells have multiple nuclei.
• Wrapped in it’s own double membrane• Houses genetic material– Consists of genes on chromosomes made from DNA– Contains all of the information and directions for
producing anything the cell needs– Sends out messages via messenger RNA (mRNA)
• DNA duplicated during cell replication
Gene Expression
More on this when we get into Proteins later in the quarter.
Endoplasmic Reticulum
• True organelle• Long network of tubes that continues off of the nucleus• Place where proteins are produced by “translating”
mRNA• Two types– Rough – associated with Ribosomes– Smooth – no ribosomes
• Other functions– Lipid synthesis– Detoxify toxic substances– Calcium storage and release
1. Nuclear membrane2. Nuclear pore3. Rough endoplasmic
reticulum (rER)4. Smooth
endoplasmic reticulum (sER)
5. Ribosome attached to rER
6. Macromolecules7. Transport vesicles8. Golgi apparatus9. Cis face of Golgi
apparatus10.Trans face of Golgi
apparatus11.Cisternae of Golgi
apparatusCourtesy of Pbroks13
Golgi Complex
• True organelle• Responsible for packaging of proteins for
export out of the cell• Packages are called secretory vesicles• Made up of multiple layers of sacs stacked on
top of one another
Lysosomes
• True organelle• Known as the “digestive system of the cell• Sacs that contain enzymes and molecules that
degrade (or digest) extracellular substances• Also degrade damaged cellular components• Very low pH (4.2) especially compared to
cytoplasm (7.2)
Peroxisomes
• True organelle• Contain enzymes responsible for detoxifying
harmful chemicals• Get their name from the formation of
hydrogen peroxide (H2O2) from enzyme activity• Contain an enzyme know as catalase– Prevents excess hydrogen peroxide accumulations
• Plays minor role in alcohol metabolism
Cell Metabolism
• Sum of all the chemical reactions in the cell• Takes place in the cytoplasm and organelles• Biochemical breakdown of food-by-products
and nutrients into usable components• Anabolic processes build and synthesize new
molecules and therefore require energy input• Catabolic processes break down nutrients and
therefore has a net energy gain
Cell Metabolism: Glycolysis and Cellular Respiration
• Primary energy yielding pathway in cells• Gycolysis: First step is the breakdown of
monosaccharides (mainly glucose); anaerobic• Products from glycolysis are moved into the
mitochondria to generate ATP; aerobic• ATP is the main energy currency in cells
DO NOT spend time trying to memorize this! It will not be on the test! I highlight this so you can understand the complexity of metabolism.
BREAK: 10 MIN
Tissues and Organ Systems
Tissues: 4 Primary Types• Epithelial
– Cells that cover both the inside and outside of the body– Secrete substances, import substances, excrete waste– Examples: lung tissue and gut tissue
• Connective– Supports and protects the body– Stores fat– Produces blood cels
• Muscle– Applies force on the connective tissue to allow for movement
• Nervous– Responsible for communication and sensory input– Examples: Brain and spinal column
Main Organ Systems
• Cardiovascular • Lymphatic• Nervous• Endocrine• Immune• Urinary • Digestive
• Integumentary• Skeletal• Muscular• Respitory• Reproductive
Cardiovascular and Lymphatic Systems
• Two different organ systems that circulate fluids– Cardiovascular System– Lymphatic System
Cardiovascular System• Primary pump in the CV is the heart
– Pumps ~50-90 beats/minute at rest• Blood is primary fluid
– Plasma– Red blood cells– White blood cells– Platelets– Other substances – ie: digested food
• Blood travels via blood vessels– Arteries – carry blood away from the heart– Veins – carry blood toward the heart– Capillaries – Smallest vessels that allow for oxygen/CO2, nutrient and waste
exchange
http://webschoolsolutions.com/patts/systems/diagcirc.gif
Lymphatic System
• Primary pump is muscle movement – the more you move the lymph flows
• Primary fluid is Lymph– Plasma– White blood cells
• Highly important for immune system• Eventually leads back to CV system• Responsible for transporting fat into the body
just after digestion – fat particles are to large to fit into capillaries
Nervous System• Regulatory system that controls most body functions• Monitors internal organs and external environment• Primary sensory organs
– Eyes– Ears– Skin– Nose– Stomach
• Responsible for muscle movement – both voluntary and involuntary
• Primary cell type is the neuron
Endocrine System• Primary system for regulating metabolism, reproduction,
water balance, and other functions• Signals by chemicals known as hormones that are
produced and secreted by endocrine glands• Hormone Function
– Permissive or excitatory – activate or turn on a signal– Antagonistic – turn off signals– Synergistic – amplify or work in cooperation with other signals
• In order for hormones to elicit function, responding cells must have corresponding receptor
Endocrine system: Examples
• Insulin – Produced by b-cells in the pancreas– Released after meal to help control blood glucose
levels– Lack of insulin or insulin function results in
diabetes• Thyroid hormones– Produced and released from the thyroid gland– Control rate of metabolism
Immune System
• Primary responsibility is to fight off infection• Works in cooperation with many other organ systems– Skin– Intestine– Bone marrow
• Primary organs– Spleen– White Blood Cells– Lymph nodes– GALT
Immune System• Two main branches
– Innate– Adaptive
• Innate immunity– Evolutionarily old– Early phase responses <7 days– Include swelling, histamine release, antigen recognition – Nonspecific
• Adaptive immunity– Found in higher order organisms– Late phase responses >7 days– Highly specific and directed response– Includes antibody production and cell killing– Provides long term immunity
Urinary system
• Comprised of kidneys, bladder, ureter, and urethra
• Responsible for filtering the blood and removing waste; primarily urine but also unused or un-needed vitamins and minerals
• Help to maintain pH balance in the blood• Responsible for conversion of Vitamin D to
erythropoietin
1. Urinary system2. Kidney3. Renal pelvis4. Ureter5. Urinary bladder6. Urethra (Left side with
frontal section)7. Adrenal gland8. Renal artery and vein9. Inferior vena cava10.Abdominal aorta11.Common iliac artery and
vein12.Liver13.Large intestine14.Pelvis
Jordi March i Nogué , 2010