1. Chapter 30 – Digestive and Excretory Systems

2. Human Body Systems

3. Human Body Organization
The Human Body
is composed of
Organ Systems
are composed of
Organs
Tissues
Cells

4. Tissues

5. Tissues
Definition: a group of closely associated cells that perform related functions and are similar in structure
Between cells: nonliving extracellular material
Four basic types of tissue…function
Epithelium…covering
Connective tissue…support
Muscle tissue…movement
Nervous tissue…control

8. “ciliated” literally = eyelashes
(see next page)

9. Glands Epithelial cells form them
Production & secretion of needed substances
Are aqueous (water-based) products
The protein product is made in rough ER, packed into secretory granules by Golgi apparatus, released from the cell by exocytosis

10. Exocrine glands unicellular or multicellular
Unicellular: goblet cell scattered within epithelial lining of intestines and
respiratory tubes
Product: mucin
mucus is mucin & water

11. Four basic types of tissue
Epithelium
Connective tissue
Connective tissue proper (examples: fat tissue, fibrous tissue of ligaments)
Cartilage
Bone
Blood
Muscle tissue
Nervous tissue

12. Connective Tissue Originate from embryonic tissue called mesenchyme
Most diverse and abundant type of tissue
Many subclasses (see previous slide)
Function: to protect, support and bind together other tissues
Bones, ligaments, tendons
Areolar cushions; adipose insulates and is food source
Blood cells replenished; body tissues repaired
Cells separated from one another by large amount of nonliving extracellular matrix

21. Four basic types of tissue
Epithelium
Connective tissue
Muscle tissue
Skeletal
Cardiac
Smooth
Nervous tissue

25. Four basic types of tissue
Epithelium
Connective tissue
Muscle tissue
Nervous tissue
Neurons
Supporting cells

27. Tissue response to injury
Immune: takes longer and is highly specific
Inflammation
Nonspecific, local, rapid
Inflammatory chemicals
Signs: heat, swelling, redness, pain
Repair – two ways
Regeneration
Fibrosis and scarring
Severe injuries
Cardiac and nervous tissue

28. Homeostasis
Organisms use homeostasis to maintain a “steady state” or internal balance regardless of external environment
In humans, body temperature, blood pH, and glucose concentration are each maintained at a constant level
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29. Mechanisms of Homeostasis
Mechanisms of homeostasis moderate changes in the internal environment
For a given variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response
The response returns the variable to the set point
Positive and Negative Feedback
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30. Figure 40.8
Figure 40.8 A nonliving example of temperature regulation: control of room temperature. 30

31. Feedback Control in Homeostasis
The dynamic equilibrium of homeostasis is maintained by negative feedback, which helps to return a variable to a normal range
Most homeostatic control systems function by negative feedback, where buildup of the end product shuts the system off
Positive feedback amplifies a stimulus and does not usually contribute to homeostasis in animals
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32. Feedback mechanisms regulate biological systems
Feedback mechanisms allow biological processes to self-regulate
Organisms use feedback mechanisms to maintain their internal environments and respond to external environmental changes.
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33. Negative feedback
Negative feedback means that as more of a product accumulates, the process that creates it slows and less of the product is produced

34. Fig. 1-13a A Negative feedback – Enzyme 1 B D Enzyme 2 Excess D
blocks a step D D C
Figure 1.13 Regulation by feedback mechanisms
Enzyme 3 D
(a) Negative feedback

35. Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced

36. Fig. 1-13b W Enzyme 4 X Positive feedback + Enzyme 5 Excess Z Z Y
stimulates a step Z Y Z
Figure 1.13 Regulation by feedback mechanisms Z
Enzyme 6 Z
(b) Positive feedback

37. Overview: The Energy of Life
The living cell is a miniature chemical factory where thousands of reactions occur
The cell extracts energy and applies energy to perform work
Some organisms even convert energy to light, as in bioluminescence
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38. An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
Metabolism is the totality of an organism’s chemical reactions
Metabolism is an emergent property of life that arises from interactions between molecules within the cell
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39. Organization of the Chemistry of Life into Metabolic Pathways
A metabolic pathway begins with a specific molecule and ends with a product
Each step is catalyzed by a specific enzyme
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40. Fig. 8-UN1 A Product Starting molecule Enzyme 1 Enzyme 2 Enzyme 3 B C
Reaction 1
Reaction 2
Reaction 3
Starting
molecule
Product

41. Catabolic pathways release energy by breaking down complex molecules into simpler compounds
Cellular respiration, the breakdown of glucose in the presence of oxygen, is an example of a pathway of catabolism
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42. The synthesis of protein from amino acids is an example of anabolism
Anabolic pathways consume energy to build complex molecules from simpler ones
The synthesis of protein from amino acids is an example of anabolism
Bioenergetics is the study of how organisms manage their energy resources
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43. An animal’s diet must supply chemical energy, organic molecules, and essential nutrients
An animal’s diet provides:
Chemical energy, which is converted into ATP to power cellular processes
Organic building blocks, such as organic carbon and organic nitrogen, to synthesize a variety of organic molecules
Essential nutrients, which are required by cells and must be obtained from dietary sources
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44. Essential Nutrients There are four classes of essential nutrients:
Essential amino acids
Essential fatty acids
Vitamins
Minerals
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45. Essential Amino Acids
Animals require 20 amino acids and can synthesize about half from molecules in their diet
The remaining amino acids, the essential amino acids, must be obtained from food in preassembled form
Meat, eggs, and cheese provide all the essential amino acids and are thus “complete” proteins
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46. Essential Fatty Acids
Animals can synthesize most of the fatty acids they need
The essential fatty acids must be obtained from the diet and include certain unsaturated fatty acids (i.e., fatty acids with one or more double bonds)
Deficiencies in fatty acids are rare
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47. Vitamins
Vitamins are organic molecules required in the diet in small amounts
Thirteen vitamins are essential for humans
Vitamins are grouped into two categories: fat-soluble and water-soluble
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48. Table 41.1
Table 41.1 Vitamin Requirements of Humans

49. Minerals
Minerals are simple inorganic nutrients, usually required in small amounts
Ingesting large amounts of some minerals can upset homeostatic balance
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50. Table 41.2
Table 4.2 Mineral Requirements of Humans

51. Dietary Deficiencies
Malnourishment is the long-term absence from the diet of one or more essential nutrients
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52. Deficiencies in Essential Nutrients
Deficiencies in essential nutrients can cause deformities, disease, and death
“Golden Rice” is an engineered strain of rice with beta-carotene, which is converted to vitamin A in the body
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53. Foods – these are necessary
Carbohydrates
Fats
Proteins
Vitamins
Minerals
water

54. Human Digestive System

55. Digestion starts in the mouth
Saliva starts mixing food
with saliva
- saliva comes from salivary
glands in the cheeks and
under the tongue.
- saliva moistens food,
mixes food with mucus, and
adds enzymes that break down
starch into sugars.

56. Teeth carry out mechanical digestion
Take care of your teeth

57. Swallowed food passes into the esophagus then the stomach
Peristalsis is responsible for pushing food in one direction through the rest of the digestive system after the mouth.
This occurs in the espophagus, stomach, small intestine, large intestine, rectum, and pushes wastes out of the anus.

63. Digestive system problems:
Food poisoning
Parasites such as worms
Viral infections (hepatitis)
Eating disorders (anorexia and bulimia)
Diarrhea and constipation
Flatulence! (excuse me!)

64. Excretory System
Animals produce waste products that must be removed from their body.
Most animals have a system that deals with nitrogen-rich wastes from the breakdown of proteins and nucleic acids.
Ammonia (NH3) is toxic.
In addition, it helps maintain homeostasis – balancing osmotic action and pH.

65. Human Excretory System

68. Excretory System Problems
Kidney stones – crystalized mineral salts and uric acid salts in the urine. Stones block flow of urine and cause excrutiating pain.
Kidney failure - can be caused by long-term diabetes, infections, physical injuries, chemical poisoning. Causes toxic materials to build up to lethal levels.
Dialysis or kidney transplant is the treatment.

69. The End