1. Animal Tissues and Organ Systems
Chapter 28
Animal Tissues and Organ Systems

2. 28.1 How Are Animal Bones Organized?
Tissue found in all vertebrate bodies:
Epithelial tissue: covers body surfaces; lines internal cavities
Connective tissue: holds body parts together; provides structural support
Muscle tissue: moves the body or its parts
Nervous tissue: detects stimuli; relays information
Insert label and caption for any figures here.

3. Levels of Organization
A Cell
(muscle cells)
B Tissue (cardiac muscle)
C Organ (heart)
Figure 28.1 Levels of organization in a vertebrate (human) body.
D Organ System (circulatory system)
E Organism (human)

4. An Internal Environment
An animal body consists mainly of water with dissolved salts, proteins, etc.
Most of this fluid resides inside cells
The rest is extracellular fluid: internal environment in which body cells live
In vertebrates, extracellular fluid consists mainly of interstitial fluid: fluid in spaces between body cells

5. Types of Connective Tissue
Cartilage: cells surrounded by a rubbery matrix of their own secretions
Adipose tissue: cells that make and store triglycerides; specialize in fat storage
Bone tissue: cells surrounded by a mineral-hardened matrix of their own secretions
Blood: plasma and cellular components (red cells, white cells, platelets)

6. Types of Connective Tissue
Figure 28.7 Blubber-encased walrus resting on an ice floe. Blubber is a special type of adipose tissue.
Like other marine mammals, walruses have a layer of blubber
beneath their skin. Fat is less dense than water, so being encased
in blubber helps a walrus float. Blubber is also springy. Unlike
most adipose tissue, it includes many collagen and elastin fibers
that cause it to spring back when compressed. This springiness
reduces the energy the walrus expends while swimming. A coat
of blubber also helps a walrus retain body heat. Even when the
outside temperature dips far below freezing, a walrus’s core body
temperature remains about the same as yours.

7. 28.5 What Are Muscle Tissues?
Muscle tissue: cells that contract (shorten) in response to stimulation
Coordinated contractions of layers or rings of muscles move the body or propel material through

8. Skeletal Muscle
Skeletal muscle tissue: helps move and maintain the positions of the body and its parts
Contains parallel arrays of long, cylindrical muscle fibers

9. Cardiac Muscle Cardiac muscle tissue: found only in the heart wall
Appears striated
Has branching cells, each with a single nucleus

10. 28.6 What Is Nervous Tissue? Nervous tissue:
Allows an animal to collect and integrate information about its internal and external environment
Controls the activity of glands and muscles
Main tissue of the vertebrate brain and spinal cord, and of the nerves that extend through the body

11. What Is Nervous Tissue?
Neurons: cells that transmit electrical signals along their plasma membrane and send chemical messages to other cells
Central cell body: contains nucleus and other organelles
Cytoplasmic extensions project from the cell body; function to receive and send electrochemical signals

12. What Is Nervous Tissue? signal-receiving extensions cell body
of neuron
signal-sending
extension
neuroglial cell
wrapped around
a signal-sending
cytoplasmic
extension of
the neuron
Figure Neuron and associated neuroglial cell.

13. What Are Vertebrate Organs and How Do They Interact?
Integumentary system: skin and skin- derived structures (e.g., hair and nails)
Nervous system: body’s main control center (brain, spinal cord, nerves, sensory organs)
Endocrine system: controls other organ systems

14. What Are Vertebrate Organs and How Do They Interact?
Muscular system: moves the body and its parts; regulates body temperature
Skeletal system: protects internal organs; stores minerals and produces blood cells
Circulatory system: heart and blood vessels; delivers oxygen and nutrients and clears wastes

15. What Are Vertebrate Organs and How Do They Interact?
food, water intake
oxygen inhaled
carbon dioxide exhaled
Digestive System
Respiratory System
nutrients, water, solutes
carbon dioxide
oxygen
Urinary System
Circulatory System
Figure Organ system interactions that keep the body
supplied with essential substances and eliminate unwanted wastes.
water, solutes
excretion of food residues
transport of materials to
and from cells
elimination of soluble wastes, excess water, and salts

16. What Are Vertebrate Organs and How Do They Interact?
Lymphatic system: moves fluid (lymph) from tissues to blood and organs; protects the body against pathogens
Respiratory system: lungs and airways; delivers oxygen from air to blood and expels carbon dioxide
Digestive system: takes in and breaks down food; delivers nutrients to blood and eliminates undigested wastes

17. What Are Vertebrate Organs and How Do They Interact?
Urinary system: kidneys, bladder, etc.; removes wastes from blood and adjusts blood volume and solute composition
Reproductive system: gamete-making organs (ovaries or testes)
In females the uterus is the organ in which offspring develop

18. 28.8 How Does Skin Structure Affect Its Function?
Components of human skin:
Epidermis: stratified squamous epithelium with an abundance of adhering junctions
Human epidermis consists mainly of keratinocytes that make the waterproof protein keratin
Dermis: consists primarily of dense connective tissue with stretch-resistant elastin fibers and supportive collagen fibers
Blood vessels, lymph vessels, and sensory receptors weave through the dermis

19. Sun and the Skin
Melanin: protects skin by absorbing ultraviolet (UV) radiation
Some UV exposure is a good thing; it stimulates skin to produce a molecule that the body converts to vitamin D
Variations in skin color among human populations probably evolved as adaptations to differences in sunlight exposure

20. Cultured Skin Products
Skin is the only organ that is grown artificially for widespread medical uses
Cells from infant foreskins are grown in culture to produce thin sheets of cells that can be used to cover wounds, burns, or sores

21. 28.9 How Do Organ Systems Interact in Homeostasis?
In vertebrates, homeostasis involves interactions among sensory receptors, the brain, and muscles and glands
Sensory receptor: responds to a specific stimulus (e.g., temperature or light)
Negative feedback mechanism: change causes a response that reverses the change
Important for homeostasis

22. 28.10 Application: Growing Replacement Tissues
Animals commonly replace tissues lost to injury
Invertebrates have the greatest capacity for regeneration
Example: some sea stars can regrow an entire body from a single arm and a bit of the central disk

23. Chapter 29
Neural Control

24. 29.1 What Are the Types of Nervous Systems?
Cell-to-cell communication is important for an animal body to function as an integrated whole
Neurons make up the communication lines of nervous systems
Neurons transmit electrical signals and send chemical messages to other cells
Neuroglial cells support the neurons
Insert label and caption for any figures here.

25. Nerve Net
Animals with radial symmetry have a mesh of interconnected neurons, a nerve net
Information flows in all directions among cells
Sea anemones and other cnidarians are simple animals with nerve net
Echinoderms have nerve net + nerves
Nerve: bundle of neuron fibers (cytoplasmic extensions) wrapped in connective tissue

26. Getting a Head
Cephalization: evolutionary trend whereby neurons became concentrated at the “head” of bilateral animals
Planarian flatworms have a simple nervous system
A pair of ganglia (cluster of neurons) in the head serves as an integrating center
The ganglia connect to a pair of nerve cords (may nerve fibers)

27. Getting a Head
Annelids and arthropods have paired nerve cords that connect to a simple brain
Brain: central control organ of nervous system

28. The Vertebrate Nervous System
A dorsal nerve cord is one of the defining features of chordate embryos
Central nervous system: brain and spinal cord (evolved from dorsal cord)
Peripheral nervous system: nerves that carry signals between the central nervous system and the rest of the body

29. The Vertebrate Nervous System
Brain
cranial nerves (twelve pairs)
cervical nerves (eight pairs)
Spinal Cord
thoracic nerves (twelve pairs)
ulnar nerve
(one in
each arm)
sciatic nerve
(one in each leg)
Figure 29.3 Some of the major nerves of the human nervous system.
lumbar nerves (five pairs)
sacral nerves (five pairs)
coccygeal nerves
(one pair)

30. How Does Neuron Structure Relate to Function?
receptor endings
peripheral axon
cell body
axon
axon terminals
cell body
axon
cell body
axon
axon terminals
dendrites
dendrites A B C
Figure 29.4 Typical structure of the three types of neurons. Arrows indicate the direction of information flow among them.

31. How Does Neuron Structure Relate to Function?
Structure of a neuron:
Cell body: contains nucleus and other organelles
Axon: transmits electrical signals and releases chemical signals at its terminal
Dendrites: receive chemical signals from other neurons

32. Conduction Along an Axon
myelin sheath
around axon
node (unsheathed region
of the axon)
Figure 29.9 Myelinated axon. Neuroglial cells produce the sheath that wraps around and insulates the axon.
axon

33. 29.5 What Happens at a Synapse?
Action potentials cannot pass directly from a neuron to another cell
Signaling molecules (neurotransmitters) relay signals between a neuron and another cell
Synapse: region where axon terminals transmit neurotransmitters to another cell

34. 29.6 How Do Drugs Act at Synapses?
Psychoactive drugs alter brain function:
Mimic a neurotransmitter’s effect on a postsynaptic cell (e.g., morphine and heroin)
Stop neurotransmitter action (e.g., caffeine)
Inhibit neurotransmitter release (e.g., alcohol)
Block reuptake of neurotransmitter (e.g., cocaine)
Slow reuptake of neurotransmitter (e.g., antidepressants)

35. 29.7 What Is the Peripheral Nervous System?
Peripheral nervous system: all nerves outside the brain or spinal cord
Each nerve has outer layer of connective tissue surrounding bundles of axons
Two major functional divisions of the peripheral system:
Somatic nervous system
Autonomic nervous system

36. What Is the Peripheral Nervous System?
Somatic nervous system: controls skeletal muscles; relays sensory signals about movements and external conditions
Autonomic nervous system: relays signals to and from internal organs and glands
Parasympathetic neurons: encourage digestion and other “housekeeping” tasks
Sympathetic neurons: activated during stress and danger

37. Chapter 31
Endocrine Control

38. 31.1 What Are Animal Hormones?
Animal hormones: intercellular communication molecules that are secreted by endocrine cells
Distributed by the blood; typically act at a distant site from their source
Only cells with the appropriate receptors (target cells) can respond to a specific hormone

39. 31.2 What Are the Components of the Human Endocrine System?
Endocrine glands: aggregations of epithelial cells that produce and secrete hormones into the blood
Collectively make up the endocrine system
Portions of the endocrine system and nervous system are closely linked
Most organs respond to hormones and signals from the nervous system

40. What Are the Components of the Human Endocrine System?
Table 31.1 Examples of Human Endocrine Glands, Their Hormones, and Hormone Actions

41. Hormonal Growth Disorders
Growth hormone production surges during teenage years, causing a growth spurt, then declines with age
Oversecretion of growth hormone during childhood leads to pituitary gigantism
Too little growth hormone during childhood can cause pituitary dwarfism

42. Hormones, Stress, and Health
Long-term elevation of cortisol is unhealthy (example: Cushing’s syndrome):
Interferes with immunity, memory, and sexual function
Raises the risk of cardiovascular problems
Abnormally low levels of cortisol (example: Addison’s disease)
Fatigue, depression, weight loss, and darkening of the skin

43. 31.7 What Are Sex Hormones?
Sex hormones: steroid hormones produced by the gonads
Essential to reproductive function
Influence secondary sexual characteristics
Traits that differ between the sexes, but do not function directly in reproduction

44. What Are Sex Hormones?
Figure 31.9 Secondary sexual characteristics. Testosterone secreted by testes stimulates growth of a male lion’s mane (left). A lioness (right) produces little testosterone, and does not develop a mane.

45. What Are Sex Hormones?
Testosterone: responsible for development of male sex organs and secondary sexual characteristics
Estrogens: function in reproduction and cause development of female secondary sexual characteristics
Progesterone: prepares a female body for pregnancy and helps maintain a pregnancy

46. How Does the Pancreas Regulate Blood Sugar?
Beta cells secrete insulin when blood glucose levels rise
Insulin causes its target cells to take up and store glucose
Encourages synthesis of fats and proteins and inhibits their breakdown
Lowers blood glucose levels

47. How Does the Pancreas Regulate Blood Sugar?
Alpha cells secrete glucagon when blood glucose levels fall
Glucagon binds to receptors on liver cells: activates enzymes that break glycogen into glucose subunits
Raises the level of glucose in blood

48. How Does the Pancreas Regulate Blood Sugar?
The regulation of blood glucose is disrupted in diabetes mellitus
Type 1 diabetes: autoimmune response destroys insulin-secreting beta cells
Symptoms usually appear in childhood and adolescence
Type 2 diabetes: target cells do not respond to insulin
Symptoms typically start in middle age

49. 31.9 Do Invertebrates Have Hormones?
Some components of the endocrine system occur in invertebrates
Example: roundworms, annelids, and mollusks make steroid hormones

50. Do Invertebrates Have Hormones?
Invertebrates do not have the same glands as vertebrates do, but they produce the homologous hormones in other glands
Example: octopuses produce estrogens, progesterone, and cortisol in a gland near their eye

51. Do Invertebrates Have Hormones?
Hormone-signaling systems unique to invertebrates have also evolved
Example: a hormone unique to arthropods called ecdysone controls molting (periodic shedding of the exoskeleton)

52. 31.10 Application: Endocrine Disrupters
DDT (a pesticide)
PCBs (used to make electronic products, caulking, and solvents)
Phthalates (found in plastics and scented products) – these chemicals are still in wide use

53. The CDC had found BPA in the urine of 95% of adults sampled in 1988–1994 and in 93% of children and adults tested in 2003–04

54. Wednesday 9/24 Chap 33,34,35,36
Friday 9/26 Chap 37,38
Wednesday 10/1 EXAM #1