Tissues, Organs, and Homeostasis Flashcards
(46 cards)
1
Q
What is homeostasis?
A
The dynamic constancy of the internal environment
2
Q
Describe Negative Feedback?
A
- Change in conditions (stimulus) occurs in body
- Change is detected by sensors
- Info. is then fed to an integrating center that compared conditions at a set point
- Message sent to effector to initiate a response
- Response bring internal conditions back to set point
- Once at set point, sensor no long detects any change
3
Q
What are antagonistic effectors?
A
Increasing activity of one effector is accompanied by a decrease in another
4
Q
Describe Positive Feedback?
A
- Do not themselves maintain homeostasis
- Response is cumulative
- Is generally part of some mechanism that does
ex. blood clotting
5
Q
What does surface area and volume effect?
A
- Mechanical demands on support structures
- Nutrient absorption rates
- Heat gain and loss
- Gas Exchange
6
Q
Describe the root system in vascular plants?
A
- Anchors plant
- Absorbs water and minerals
7
Q
Describe the shoot system in vascular plants?
A
- Supporting stems
- Photosynthetic leaves
- Reproductive flowers
8
Q
Describe the cell walls in plants?
A
- Made of mainly cellulose
- Primary cell wall: found in all cells
- Secondary cell wall: found in some cells, increase mechanical strength of wall
9
Q
Explain the three different tissue systems in roots, shoots, and leaves?
A
- Dermal tissue: for protection, wax and bark
- Ground tissue: for storage, photosynthesis, and secretion
- Vascular tissue: for conduction, xylem (water and dissolved minerals), phloem (nutrient containing solution)
10
Q
What are meristems?
A
- Clumps of small cells with dense cytoplasm and large nuclei
- Act as stem cells do in animals (one cell divides producing a different cell or one that remains meristematic)
11
Q
What are apical meristems?
A
- Located at tips of stems and roots
- Give rise to primary tissues
- The three primary meristems give rise to the three major types of plant tissue
12
Q
What are lateral meristems?
A
-Exhibit secondary growth increasing the size of stems and roots
13
Q
Describe dermal tissue?
A
- Forms the epidermis (usually only one cell layer thick)
- Cuticle
- Contains special cells: guard cells, trichomes, and root hairs
14
Q
Describe Guard cells?
A
- Part of dermal tissue
- Flank a stomata, which is the passageway for oxygen and carbon dioxide
15
Q
Describe Trichomes?
A
- Part of dermal tissue
- Uni or multicellular growths of epidermis
- Keep leaf surface cool and reduce evaporation
- Some are glandular secreting substances that deter herbivores
16
Q
Describe Root Hairs?
A
- Part of dermal tissue
- Tubular extensions of individual epidermal cells
- Increase the root’s surface area and efficiency of absorption
17
Q
What three cells types are in ground tissue?
A
- Parenchyma
- Collenchyma
- Sclerenchyma
18
Q
Describe Parenchyma cells?
A
- Part of ground tissue
- Most common type of plant cell
- Provides storage, photosynthesis, secretion, provide little to no support
19
Q
Describe Collenchyma cells?
A
- Part of ground tissue
- Flexible support for plant organs
20
Q
Describe Sclerenchyma?
A
- Part of ground tissue
- Thick walled and dead at maturity
- Lignin
- Two types:
1. Sclerids: can make up outside, hard
2. Fibers
21
Q
What makes up vascular tissue?
A
- Xylem: water and mineral conducting tissue
- Vessels: continuous tubes of dead cylindrical cells
- Tracheids: dead cells that taper at the end and overlap on another
- Phloem: main food conducting tissue (sieve cells and sieve tube members which are associated with companion cells which is life support)
- Vessels are shorter and wider than tracheids and conduct water more efficiently
22
Q
What are the four main regions of roots?
A
- Root cap: functions in protection of delicate tissues behind it
- Zone of cell division: Rapid divisions of the root apical meristem
- Zone of elongation: Roots lengthen because cells become longer, no further increase in length occurs above this zone
- Zone of maturation: elongated cells become differentiated into specific cell types, vascular tissue is surrounded by endodermis, ground tissue (now cortex) is surrounded by epidermis (which grows root hairs), Caspian strip (watertight layer between endodermis cells, water can’t travel between cells so it must travel through them), secondary growth in woody plants (vascular cambium is a ring of meristematic tissue surrounding the xylem, causes laters growth of xylem expanding root width)
23
Q
Describe Stems?
A
- Contain three types of plant tissues
- Shoot apical meristem produces primordia (develops into leaves, other shoots and flowers)
24
Q
Describe the external stem structure?
A
- Node: point of attachment of leaf to stem
- Internode: area of stem between two nodes
- Blade: flattened part of leaf
- Petiole: stalk of leaf
- Axil: angle between petiole/blade and stem
- Axillary bud: develops into braces with leaves or flowers
- Terminal bud: extends the shoot system during the growing season
25
Describe the internal stem structure?
- Certain plants have vascular bundles scattered throughout
| - Others have vascular tissue arranged in a ring with internal ground tissue (pith) and external ground tissue (cortex)
26
Describe the internal stem structure?
- Vascular cambium: located between xylem and phloem (in roots) and expands stem width by growing new xylem
- Periderm: outside phloem, has meristematic cork cambium that produces cork cells for bark
- Light rings: less or larger vessels
- Dark rings: more or smaller vessels
- Cork tissues die shorty after they are formed and constitute outer bark
- Cork cambium also produces cells called lenticels
27
Describe leaves?
- Main site of photosynthesis
- Determinate growth (predetermined size)
- Veins consist of both xylem and phloem and are distributed throughout leaf blades
- Waste accumulation
- May be arranged in three ways: alternate (most common), opposite, whorled
28
Descrive leaf blades?
- Simple leaves contain undivided blades
| - Compound leaves have blades that divide into leaflets
29
Describe leaf surface?
- Surface is covered by transparent epidermal cells
| - Epidermis has a waxy cuticle
30
Describe mesophyll?
- Some leaves have one type of mesophyll
- Others have two types: Palisade mesophyll (usually two rows of tightly packed cells), or spongy mesophyll (loosely arranged cells with air spaces
31
What are the four levels of organization in animals?
- Cells
- Tissues
- Organs
- Organ System
32
Describe cells?
- Smallest division of life
- All life is cellular
- All cells come from preexisting cells
33
Describe tissues?
-Group of cells that are similar in structure and function
34
Describe organs?
-Combinations of different tissues that form a structural and functional unit
35
Describe organ systems?
- Groups of organs that cooperate to perform the major activities of the body
- Vertebrate body contains 11 principle organ systems
36
Describe the body plan?
- Inner tube: digestive tract
| - Outer tube: main vertebrate body, supported by a skeleton, outermost layer (skin and its accessories)
37
Describe the types of tissues in vertebrates?
```
-Primary tissues:
Epithelial
Connective
Muscle
Nervous
```
38
Describe Epithelial tissues?
- Epithelium covers exposed surfaces of the vertebrate body
- All germ layers have it
- Can be membranes or glands
- Provide protective barrier
- Tightly bound
- Replaced throughout life
- Attach to underlying connective tissues by fibrous membrane
- Epithelium has polarity (basal surface: secured side, Apical surface: free side)
39
What are the Epithelial type?
- Layers: one layer allows for diffusion, absorption, and secretion, several layers creates a dense barrier to abrasion and chemicals
- Cell size: flat cells allow materials to diffuse through, cubed cells absorb and secrete moderately, thick cells absorb, secrete, and process chemicals at the greatest rate
40
Describe glands?
- Form from invaginated epithelia
- Exocrine glands: connected to epithelium by a duct, sweat, sebaceous and salivary glands
- Endocrine glands: ductless, secretions (hormones) enter blood
41
Describe connective tissues?
- Derived from embryonic mesoderm
- All have abundant extracellular material
- Two major classes: Connective tissue proper (loose, dense, adipose), Special connective tissue (cartilage, bone, blood)
- Consists of: Matrix (extracellular material) and cells that produce the matrix
- Fibroblasts: cells that produce and secrete protein fibers in extracellular matrix (includes thick collagen fibers and stretchable elastic fibers)
42
Describe connective tissue proper?
- Loose connective tissue: contains large amounts of gel-like substances and is strengthened by protein fibers
- Dense connective tissue: contains less gel and more collagen, collagen fibers may be parallel to one another or go in many different directions
- Adipose cells also occur in loose connective tissue (insulation and long term energy storage)
43
Describe special connective tissue?
- Cartilage: Chondrocytes (cartilage cells)
- Matrix: chondroitin, collagen/elastic fibers
- Flexible with great strength
- Bone: Osteocytes (bone cells), hardened with calcium salts around collagen fibers
- Blood: Extracellular materials is the fluid plasma, red blood cells (carry O2), white blood cells (fighting), platelets (clotting)
44
Describe muscle tissue?
- Smooth muscles: walls of blood vessels and visceral organs
- Mono-nucleated
- Involuntary
- Skeletal muscles: attached to bone by tendons
- Cells long and multi-nucleated
- Voluntary
- Striated
- Cardiac muscle: smaller, interconnected cells in heart only
- Mono-nucleated
- Interconnections called intercalated disks
- muscle cells form a single functioning unit
45
Describe nerve tissue?
- Neurons consist of three parts:
- Cell body: contains nucleus
- Dendrites: highly branched extensions (conduct electrical impulses toward cell body)
- Axon: single cytoplasmic extension (conducts impulses away from cell body)
- Neuroglia: don't conduct electrical impulses
- Supports and insulated neurons
- Eliminates foreign materials in and around nucleus
- Form an insulating cover
46
Describe organ systems?
- Communication and integration:
- Nervous, sensory, endocrine
- Support and movement: musculoskeletal system consists of two interrelated organ systems
- Regulation and maintenance:
- Digestive, circulatory, respiratory, urinary systems
- Defense:
- Integumentary, Immune
- Reproduction and development: (spreading genes, nurtures embryo/fetus)
- Reproductive system
