Organisations of the Human body

Question 1

What are cells?

Answer 1

Smallest component of the body
Basic functions
Independent entity
Role in homeostasis

Question 2

what are the jobs unspecified cells?

Answer 2

These cells multiply continuously to replace the millions of different body cells that die and need to be replaced every day.

Question 3

cell membrane

Answer 3

Cell membrane— a phospholipid bilayer which also contains cholesterol andproteins; its functions are to provide support and to control entrance and exit of all materials. We will discuss the structure of thecell membraneand the mechanisms by whichchemicalscan penetrate or be absorbed into or out of thecell.

Question 4

cytoplasm

Answer 4

Cytoplasm— a watery solution of minerals, organic molecules, and gases found between thecell membraneandnucleus.

Question 5

nucleus

Answer 5

Nucleus— a membrane-bound part of acellthat contains nucleotides,enzymes, and nucleoproteins; thenucleuscontrolsmetabolism,proteinsynthesis, and the storage and processing of genetic information.

Question 6

cytosol

Answer 6

Cytosol— the liquid part of thecytoplasmwhich distributes materials bydiffusionthroughout thecell

Question 7

nucleolus

Answer 7

Nucleolus— a dense region of thenucleuswhich contains theRNAandDNA; It is the site for rRNA synthesis and assembly of the ribosome components.

Question 8

Endoplasmic reticulum

Answer 8

Endoplasmic reticulum— an extensive network of membrane-like channels that extends throughout thecytoplasm; it synthesizes secretory products and is responsible for intracellular storage and transport.

Question 9

Ribosomes

Answer 9

Ribosomes— very small structures that consist ofRNAandproteinsand performproteinsynthesis; someribosomesare fixed (bound to theendoplasmic reticulum) while otherribosomesare free and scattered within thecytoplasm

Question 10

Mitochondria

Answer 10

Mitochondria— ovalorganellesbound by a double membrane with inner folds enclosing important metabolicenzymes; they produce nearly all (95%) of theATPand energy required by thecell

Question 11

Lysosomes

Answer 11

Lysosomes— vesicles that contain strong digestiveenzymes;lysosomesare responsible for the intracellular removal of damagedorganellesor pathogens.

Question 12

Peroxisomes

Answer 12

Peroxisomes— very small, membrane-boundorganelleswhich contain a large variety ofenzymesthat perform a diverse set of metabolic functions.

Question 13

Golgi apparatus

Answer 13

Golgi apparatus— stacks of flattened membranes containing chambers; they synthesize, store, alter, and package secretory products.

Question 14

Centrioles

Answer 14

Centrioles— there are twocentrioles, aligned at right angles, each composed of 9 microtubule triplets; they organize specific fibers of chromosomes duringcelldivision, which move the chromosomes

Question 15

Cilia

Answer 15

Cilia— thread-like projections of the outer layer of thecell membrane, which serve to movesubstancesover thecellsurface.

Question 16

how many tissues are dispersed throughout the body

Answer 16

4

Question 17

name the 4 types of tissues in the body

Answer 17

Epithedial tissues
connective tissues
muscle tissues
nerve tissues

Question 18

Epithedial tissues

Answer 18

Protects (physical protection,) absorbs, secretes substances (sweat) and detected sensations (conveying information to the nervous system)

Question 19

connective tissues

Answer 19

Connective tissuesprovide support and hold the bodytissuestogether. They contain more intercellularsubstancesthan the othertissues.Connective tissuesinclude blood; bone; cartilage; adipose (fat); and the fibrous and areolar (loose)connective tissuesthat give support to mostorgans

Question 20

muscle tissues

Answer 20

specialized for an ability to contract. Musclecellsare elongated and called muscle fibers. When one end of a musclecellreceives astimulus, a wave of excitation is conducted through the entirecellso that all parts contract in harmony.

Question 21

nerve tissues

Answer 21

Nervous tissueis specialized with a capability to conduct electrical impulses and convey information from one area of the body to another. Most of thenervous tissue(98%) is located in thecentral nervous system, the brain, and spinal cord.
There are two types ofnervous tissue: 1)neuronsand 2)neuroglia.Neuronsactually transmit the impulses.Neuroglia(Figure 6) provide physical support for the neuraltissue, controltissuefluids around theneurons, and help defend theneuronsfrom invading organisms andxenobiotics.Receptornerve endings ofneuronsreact to various kinds of stimuli (for example, light, sound, touch, and pressure) and can transmit waves of excitation from the farthest point in the body to thecentral nervous system.

Question 22

skeletal muscle

Answer 22

attached to bone and contracts causing the bones to move.

Question 23

Cardiac muscle

Answer 23

contracts to force blood out of the heart and around the body.

Question 24

smooth muscle

Answer 24

an be found in severalorgans, including the digestive tract, reproductiveorgans, respiratory tract, and the lining of the bladder. Examples of smooth muscle activity are the:
Contraction of the bladder to force urine out.
Peristaltic movement to move feces down thedigestive system.
Contraction of smooth muscle in the trachea and bronchi which decreases the size of the air passageway.

Question 25

describe the structure of skeletal muscle

Answer 25

Has Three layers of connective tissue — Mysia
Wrapped in sheath (epimysium)
Axon branch of a somatic neuron (signals contraction)
Sarcomere?
Neuromuscular junction