Understanding Human Cell Structure and Function

1. Chapter 7 Anatomy and Physiology

2. 7:1 Basic Structure of the Human Body • The normal function of the human body is compared to an organized machine • The machine malfunctions, disease occurs • Anatomy: study of form and structure • Physiology: study of processes • Pathophysiology: study of how disease occurs and body’s response

3. Protoplasm • Basic substance of life (represents the living part of the cell) • Made of ordinary elements (e.g., carbon, oxygen, hydrogen) • Scientists can combine these elements, but not create life • Protos is greek for “first” and plasm represents “things formed”

4. Cells • Microscopic organisms that carry on all functions of life • Body contains trillions of cells • Vary in shape and size • Perform different functions • Page 143

5. Basic Parts of Cells • Cell membrane – the outer protective covering of a cell. It is called the plasma membrane and is considered semipermeable (allows certain cells to come and go but not others) • Cytoplasm – a semifluid inside the cell but outside the nucleus. It is the site for all chemical reactions that take place in a cell. • Organelles – cell structures that help a cell to function and are located in the cytoplasm (main organelles are the nucleus, mitochondria, ribosomes, lysosomes, centrioles, golgi apparatus, etc.) • Nucleus – a mass in the cytoplasm. It is separated from the cytoplasm by a nuclear membrane that contains pores to allow substances to pass between the nucleus and cytoplasm. It is called the “brain” of the cell (continues)

7. Basic Parts of Cells(continued) • Nucleolus – one or more small round bodies found in the nucleus, and important to cell reproduction. Ribosomes are manufactured in the nucleus • Chromatin – located in the nucleus and made of DNA and protein. During cell reproduction the chromatin condenses to form a chromosomes. • A human cell has 46 chromosomes or 23 pairs. Each chromosome contains between 30,000 to 45,000 genes. Each gene has a specific and unique sequence of 1000 base pairs of DNA. • Genome – total mass of genetic instruction humans inherit from their parents. (continues)

8. Basic Parts of Cells (continued) • Centrosome – located in the cytoplasm and near the nucleus and it contains two centrioles. It helps distribute chromosomes. • Mitochondria – rod-shaped organelles located throughout the cytoplasm. They are called “powerhouses” of the cell because they break down carbs and fats to produce energy. • Golgi apparatus – a stack of membrane layers located in the cytoplasm. Produces, stores, and packages secretions from cells. Cells of the salivary, gastric, and pancreatic glands have many of these.

9. Basic Parts of Cells (continued) • Endoplasmic reticulum – a fine network of tubular structures located in the cytoplasm. Allows for transport of materials to the nucleus. • Ribosomes – sites for protein synthesis and located on rough ER. • Vacuoles – pouchlike structures found throughout the cytoplasm. Filled with watery substance, store food, and waste products. • Lysosomes – oval or round bodies found throughout the cytoplasm. Contain digestive enzymes that destroy old cells, bacteria, etc. • Pinocytic vesicles – pocketlike folds in the cell membrane. These folds allow for large molecules such as proteins and fats to enter the cell.

10. Cell Structure • https://www.youtube.com/watch?v=URUJD5NEXC8

11. Mitosis • Asexual reproduction process used by most cells • Different types of cells reproduce at different rates • Skin, blood, and intestinal cells reproduce continuously • Muscle cells reproduce every few years • Specialized cells such as the brain or spinal cord do not reproduce after birth • Process of mitosis—see Figure 7-2 in text page 144

12. Meiosis • Process by which sex cells reproduce • Uses two separate cell divisions • Female cells (ova) and male cells (spermatozoa or sperm) divide to produce 23 chromosomes each • When ova and sperm combine, 46 chromosomes result to form zygote (new cell) • The zygote begins a period of rapid division. Within 4-5 days the zygote is a mass of cells called a blastocyst • The blastocyst contains stem cells which have the ability to transform themselves into any of the body’s specialized cells. • Stem cells have become a controversial topic as doctors attempt to program stem cells to replace damaged cells or cure diseases.

13. Meiosis vs Mitosis • Meiosis • https://www.youtube.com/watch?v=nMEyeKQClqI • https://www.youtube.com/watch?v=qCLmR9-YY7o • Mitosis • https://www.youtube.com/watch?v=ofjyw7ARP1c • Mitosis vs Meiosis • https://www.yourgenome.org/facts/mitosis-versus-meiosis

14. Stem Cells • Controversy arises from the fact that a 4-5 day embryo is capable of creating new life, yet is used to gather stem cells instead. • Advocates for right to life are strictly against stem cell research • Another way to obtain stem cells is from the blood in a babies umbilical cord and placenta. Mothers are now given the option to freeze this blood incase the child develops a disease that can be cured with stem cells. • Adults have stem cells also in their bone marrow and liver yet they do not have the ability to evolve into every kind of cell. • https://www.youtube.com/watch?v=JIrJK6uE3XY

15. Tissues • Cells of same type joined together • 60%–99% water • This water is slightly salty and is called tissue fluid. If there is not enough fluid dehydration can occur. When there is too much fluid a condition called edema can occur which is swelling of the tissues. • Groups of tissues (four main groups) • Epithelial – covers the surface of the body and is the main tissue of the skin(respiratory, intestinal, and urinary lining) • Connective – is the supporting fabric of organs and other body parts and can be soft or hard (soft – ligaments and tendons / hard – cartilage and bone / blood – liquid tissue) • Nerve – is made up of special cells called neurons and it controls and coordinates body activities • Muscle - produces power and movement by contraction of muscle fibers

16. Four types of tissues • https://www.youtube.com/watch?v=i5tR3csCWYo

17. Muscles • Produces power and movement by contraction of muscle fibers. • There are three main types of muscle tissue: • Skeletal – attach to bones and provide movement • Cardiac – cause the heart to beat • Visceral – present in the walls of the respiratory, digestive, urinary tract, and blood vessels

18. Organs and Systems • Organs: two or more tissues joined together for a specific purpose (heart, stomach, lungs) • Systems: organs and other body parts joined together for a particular function • The basic systems are the integumentary (hair skin nails), skeletal, muscular, circulatory, lymphatic, nervous, respiratory, digestive, urinary, endocrine, and reproductive • (camera page 146)

19. Summary • Protoplasm is basic substance of life • Protoplasm forms structural units called cells • Cells combine to form tissue • Tissues combine to form organs • Organs and other parts combine to form systems • Systems work together to create miracle of human body

20. 7:2 Body Planes/Directions/Cavities • Body planes: imaginary lines drawn through body at various levels to separate body into sections • Directional terms are created by planes • Transverse plane – is a horizontal plane that divides the body into a top and bottom half • Midsagittal or median plane – divides the body into left and right sides • Frontal or coronal plane – divides the body into a front and back section • Proximal and distal – describes the location of extremities in relation to the trunk of the body (proximal is close distal is further away) • (camera page 149)

21. Cavities • Spaces within the body that contain vital organs • Dorsal or posterior – is one long continuous cavity located on the back of the body and is divided into two sections • Cranial cavity – contains the brain • Spinal cavity – contains the spinal cord • Ventral or anterior cavities – are larger than the dorsal cavity and located on the front of the body • Thoracic cavity – is located in the chest and contains the esophagus, trachea, lungs, heart, etc. • Abdominal cavity – contains the stomach, small intestine, some large intestine, appendix, and pancreas. • Pelvic cavity – contains the urinary bladder, reproductive system, and the last part of the large intestine

23. Cavities • Three small cavities • Orbital – for the eyes • Nasal – for the nose structure • Buccal – for the mouth, teeth, and tongue

24. Abdominal Regions • Abdominal cavity is separated into regions or sections because it is so large • Quadrants • RUQ (right upper) • LUQ (left upper) • RLQ (right lower) • LLQ (left lower) (continues)

25. Abdominal Regions (continued) • Regions • Epigastric • Umbilical • Hypogastric • Hypochondriac • Lumbar • Iliac or inguinal • (camera page 150)

26. 7:3 Integumentary System • Name for the skin and its structures • Called a membrane because it covers the body • Called an organ because it contains several kinds of tissues • Most professionals call it a system because it has organs and other parts that work together for a particular function • On average, the skin covers 3000 square inches of surface area and accounts for about 15 percent of total body weight

27. Layers of the Skin • Epidermis—outermost layer of skin that is made up of five smaller layers of skin but no blood vessels or nerve cells. The outer layer of skin constantly sheds while the innermost layer replaces the cells • Dermis—“true skin” contains elastic connective tissue and contains blood vessels, lymph vessels, nerves, sweat, oil glands, and hair follicles • Subcutaneous fascia or hypodermis—the innermost layer made of elastic and fibrous connective tissue and fatty tissue and connects the skin to underlying muscles • (page 53 of med term) • https://www.youtube.com/watch?v=Orumw-PyNjw

28. Glands and Other Parts of the Skin • Sudoriferous glands (sweat glands) – coiled tubes that extend through the dermis and open on the skin surface. Sweat contains water, salts, and some body wastes but is usually odorless. When sweat interacts with bacteria smell occurs. • Sebaceous glands (oil glands) – they produce sebum, an oil that keeps the skin and hair from becoming dry. Sebum is acidic and can act as an antibacterial. When the oil gland becomes plugged, blackheads or pimples occur. • Hair – grows in a hollow tube called a follicle • Nails – can regrow as long as the nail bed is not lost

29. Functions • Protection – serves as a barrier to sun’s rays and germs • Sensory perception – the nerves in the skin help the body respond to pain, pressure, temp, and touch • Regulation of body temperature – blood vessels in the skin help the body retain or lose heat • Storage – the skin has tissues for temporary storage of fat, glucose, water, vitamins, and salts • Absorption – certain substances can be absorbed through the skin such as medication (transdermal meds) • Excretion – the skin helps the body eliminate salt, a small amount of waste, and excess heat and water • Production – the skin helps with production of vitamin D by using ultraviolet rays from the sun to form the beginnings of vitamin D

30. Skin Color—Pigmentation • Skin color is inherited and is determined by pigments in the epidermis • Melanin – brownish black pigment that is produced in the epidermis and genes from each racial group determine the number of melanin produced • Melanin can lead to black, brown, and yellow skin tint depending on what skin color is present • Ultraviolet light activates melanin to form more pigments to protect and tan the skin, small concentrations of melanin form freckles

31. Skin Color—Albino • Absence of skin pigments • Skin has pinkish tint • Hair is pale yellow or white • Eyes are red in color and sensitive to light • https://www.youtube.com/watch?v=cHRM2S_fBOk

32. Skin Color—Abnormal • Erythema – is a reddish color of the skin that can be caused by burns or congestion of blood vessels • Jaundice – a yellow discoloration of the skin, can indicate bile in the blood as a result of liver and gallbladder disease • Cyanosis – is a bluish discoloration of the skin caused by insufficient oxygen • https://www.youtube.com/watch?v=EN-x-zXXVwQ

33. Skin Eruptions • Macules (macular rash) – flat spots on the skin, such as freckles (pg. 60 mt) • Papules (papular rash) – firm raised areas such as pimples and eruptions (pg. 61 mt) • Vesicles – blisters or fluid filled sacs (pg. 62 mt) • Pustules – pus-filled sacs (pg. 62 mt) • Crusts – areas of dried pus or blood (scabs) • Wheals – itchy, elevated areas with an irregular shape (pg. 63 mt) • Ulcer – a deep loss of skin surface that may extend into the dermis; may cause bleeding or scars (pg. 62 mt)

34. Skin Burns • First degree – superficial first degree burns in the epidermis • Second degree – partial thickness second degree burns in the epidermis and dermis • Third Degree – full thickness third degree burns in the deep tissue (pg. 64 mt) https://www.youtube.com/watch?v=Dsvtzwp4nG8

35. Skin Grafts • Allograft – skin taken from one person and given to another. Is commonly referred to ad a cadaver https://www.youtube.com/watch?v=RpcFxRAkVpI • Autograft – skin graft taken from a person’s own body https://www.youtube.com/watch?v=31OaRPgmEZc

36. Diseases and Abnormal Conditions • Acne vulgaris – also known as acne, the cause is unknown yet we do recognize the it happens most during adolescence. Hormonal changes and excessive oil in the sebaceous gland contribute to acne (old age=dry) • https://www.youtube.com/watch?v=lAx5gwhmsdo • https://www.youtube.com/watch?v=KI6Sqybay4Y • Athlete’s foot – a contagious fungal infection that usually affects the feet. The skin itches, blisters, and cracks into open sores • Skin cancer – the most common form of cancer • Basal cell carcinoma • Squamous cell carcinoma (pg. 66 & 67) • Melanoma (continues)

37. Diseases and Abnormal Conditions (continued) • Dermatitis – an inflammation of the skin, can be caused by an allergic reaction to detergents, cosmetics, pollen, or certain foods • Eczema – a noncontagious, inflammatory • Impetigo – highly contagious skin infection usually caused by strep or staph organisms. Antibiotics and topical treatments should be used.

38. Diseases and Abnormal Conditions (continued) • Psoriasis – Psoriasis is a chronic, noncontagious skin disease with periods of outbreaks and remissions. The cause is unknown but the link may be hereditary • Ringworm – a highly contagious fungai infection of the skin or scalp. The characteristic symptoms are the formation of a flat or raised circular area with a itchy or scaly outer ring • Verrucae/warts/plantar warts – caused by viral infection of the skin. Some warts disappear spontaneously while others must be treated

39. Surgical Procedures • Cryosurgery – use of extreme cold to freeze and destroy tissue • https://www.youtube.com/watch?v=K7DkK8myhj4 • Debridement – removal of foreign material and dead or damaged tissue from a wound • https://www.youtube.com/watch?v=GKIEIdMFMwI • Electrocautery – to destroy tissue with an electric current • https://www.youtube.com/watch?v=EiRifKSHsEE • Onychectomy – removal of a nail or portion of a nail • https://www.youtube.com/watch?v=_LJ8e0dZChg

40. 7:4 Skeletal System • Made of organs called bones • Adult has 206 bones • Serves as framework for muscles, fat, and skin • Protects internal structures • Produces blood cells • Stores calcium, phosphorus, and fats • https://www.youtube.com/watch?v=rDGqkMHPDqE

41. Long Bones • Bones of the extremities are called “long bones” • Diaphysis – the long shaft of the bone • Epiphysis – the ends of the bone • Medullary canal – the cavity within the shaft or diaphysis • Yellow marrow – is mainly a storage for fat cells (continues)

42. Long Bones (continued) • Endosteum – the membrane that lines the inner medullary cavity and keeps the marrow intact • Red marrow – produces red blood cells and is found in the certain bones (ribs, sternum, etc.) and in the ends of the humerus and femur • Periosteum – tough membrane on the outside of the bone that is important to bone growth, repair, and nutrition • Cartilage – shock absorbers for the ends of bones where they meet • (Pg. 158 DHO) • (pg. 87 MT) • https://www.youtube.com/watch?v=q4vXr9IuPVc

43. Skeleton • Axial • Main trunk of body • Skull, spinal column, ribs, and sternum • Appendicular • Extremities • Shoulder girdle, arm bones, pelvic girdle, and leg bones

44. Skull • Cranium holds the brain and is composed of eight bones • Fontanels – soft spots that allow for the enlargement of the skull for brain growth • Sutures – are areas where the cranial bones have joined together • Sinuses – are air spaces in the bones of the skull that act as resonating chambers for voice • Foramina – are openings in the bones that allow for blood vessels and nerves to enter or leave the bone • https://www.youtube.com/watch?v=QYK2I50pTdw • https://www.youtube.com/watch?v=M7SEQ4DlhKQ

45. Cranial Bones • Eight bones of skull that surround and protect the brain • Frontal • Parietal (2) • Temporal (2) • Occipital • Ethmoid • Sphenoid

46. Facial Bones • 14 bones of skull that form facial features • Mandible—lower jaw • Maxilla (2)—upper jaw • Zygomatic (2)—cheek • Nasal (5)—upper part of nose • Lacrimal (2)—inner aspect of eye • Palatine (2)—hard palate (roof of mouth) • (Pg. 158 DHO)

47. Vertebrae • Spinal column—26 bones • Protects the spinal cord • Supports head and trunk • Cervical (7)—neck • Thoracic (12)—chest, attach to ribs • Lumbar (5)—waist • Sacrum (1)—back of pelvic girdle • Coccyx (1)—tailbone • (Pg. 159 DHO) • https://www.youtube.com/watch?v=NAd9g5nUurE • https://www.youtube.com/watch?v=0qR-Yfw9fOI

48. Intervertebral Disks • Pads of cartilage separating vertebrae • Act as shock absorbers • Permit bending and twisting movements • https://www.youtube.com/watch?v=3VCS4QDETac

49. Ribs (costae) • 12 pairs of long slender bones • Attach to thoracic vertebrae • True ribs—first 7 pairs; attach to sternum • False ribs—last 5 pairs

50. Sternum • Breastbone • Consists of 3 parts • Two clavicles attach • Ribs attach with cartilage • Manubrium (top) • Gladiolus (body or center) • Xiphoid process (bottom) • Xiphoid - At birth, it is a thin, roughly triangular region of cartilage which gradually turns into bone in adulthood and forms part of the sternum. It is used by numerous muscles especially the abdominal diaphragm.