Describe how skin changes as we age




Bio201 Exam #1 Short-Answer Essay Questions:

51. Explain how epithelial tissue is classified according to the number of cell layers and the shape of the cells.

Classification According to Shape

There are four shapes of epithelial cells, namely; squamous, cuboidal, transitional, and columnar. Squamous cells have a flat form due to the thin cells which have a flattened nucleus. Cuboidal cells have a cube-like way with a round nucleus at the centre. Columnar cells have a column shape with tall cells that have an oval nucleus. Transitional cells are different from the above because they change shape on various occasions. When the tissue is relaxed, the apical cells assume a cuboidal form and squamous when the tissue is stretched (Page, 52)

Classification According to the Number of Cell Layers

Simple epithelium tissue has only one cell layer, whereas stratified epithelium refers to the epithelium tissue with two or more cell layers. Simple epithelium works by providing a barrier allowing diffusion, secretion, absorption to take place. The stratified epithelium is thicker its purpose is to provide a protective layer and is subject to wear and tear (Page, 52)

What is pseudostratified columnar and transitional epithelium?

Pseudostratified columnar epithelium works by giving an illusion of several different layers of cells when, in real sense, there is only one cell layer thick. Transitional epithelium found at the lining of the urinary bladder and other parts like the ureters and the urethra. The transitional epithelium works by providing a protective barrier that allows distension (Page, 58)

52. Explain how some aspects of skin cells demonstrate form follows function.

Some of the skin cells that demonstrate the form-follows-rule include the cells of the human skin epidermis. The epidermis is made of cell layers referred to as squamous epithelium. Cells of the epithelium have a way that they are joined together forming a sturdy flat surface, which makes the cells die over time. A combination of the thickness of the epidermis, the adhesion of one cell to another, and the dry layer of dead cells provide a protective coating. The coating prevents water loss, prevents the entry of microorganisms, and help maintain homeostasis (Page, 52)


Bio201 Exam #1 Study Guide:

Use this study guide to help you review the critical information you should know from your notes to be prepared for your exam.

I. The organization of the Human Body

· Distinguish between anatomy and physiology

Anatomy is the study of the structure of the body whereas physiology studies the function of the body (AP lecture 1A slide 2 and 4)

· Describe the relationship between anatomy and physiology and give an example of how form follows function in the human body

The purpose of different organs in the body goes hand in hand with the structure of the organ. For example, bones in the body can offer support due to hard mineral deposits in it. Also, backflow of blood cannot happen due to the valves present in the heart (AP lecture 1A slide 6)

· Identify the body’s structural levels of organization (cells to the organism)

Chemical level, cellular level, tissue level, organ level, organ system level, and organism level (AP lecture 1A slide 7)

· Identify the level of the organization considered to be the basic unit of life

Chemical level (AP lecture 1A slide 8)

· Identify the major structures and functions of organ systems we will cover in Anatomy.

The functions include; maintain boundaries, movement, responsiveness, digestion, and metabolism, dispose of wastes, reproduction, and growth. Structures include; bones, hair, brain, ovaries to name a few (AP lecture 1A slide 15, 22, and 23)

· Describe the functions necessary for life and body systems that help to carry out those function

The features include; maintain boundaries, movement, responsiveness, digestion, and metabolism, dispose of wastes, reproduction, and growth. Structures include; bones, hair, brain, ovaries to name a few (AP lecture 1A slide 15, 22, and 23)

· Describe factors that the body needs to survive

Nutrients, oxygen, water, average body temperature, and appropriate atmospheric pressure (AP lecture 1A slide 33)

· Define homeostasis and understand the basic principles of homeostasis

All organ systems in the bodywork together to maintain relatively stable internal conditions despite changes in the environment (AP lecture 1A slide 36)

· Identify the body systems involved in the maintenance of homeostasis

Every organ system plays a role in ensuring an equilibrium is maintained in the internal environment (AP lecture 1A slide 36)

· Identify the components of homeostatic control mechanisms

Receptor, control centre, and effector (AP lecture 1A slide 38)

· Given an example of a homeostatic mechanism, identify the parts

Body’s thermostat an example of homeostatic mechanism. When body temperature falls, the receptor, which is the sensitive cells in the skin and brain feels the drop of temperature and sends messages to the control centre. The control centre which is the thermoregulatory centre in mind, finds the necessary response and sends the answer to the effectors. The effector’s skeletal muscles trigger shivering which causes the body temperature to rise (AP lecture 1A slide 44)


· Distinguish between positive and negative feedback mechanisms

A positive feedback mechanism description takes the form of enhancing the original stimulus to accelerate response. The change that occurs after that follows the same direction as the initial making the variable change further from its unique value. Negative feedback mechanism responses shut off original stimulus making the variables to improve in the opposite direction from the initial move (AP lecture 1A slide 45 and 48)

· Give examples of positive and negative feedback mechanism

Examples of positive feedback include; enhancement of labour contractions by oxytocin and platelet plug formation and blood clotting. Negative feedback example include; regulation of body temperature, and regulation of blood glucose (AP lecture 1A slide 48 and 45)

· Describe the consequences of being unable to maintain homeostasis

Increased risk of contracting diseases, body control systems becoming less efficient, and destructive positive feedbacks may take over (AP lecture 1A slide 54)



II. Language of Anatomy

· Describe anatomical position

The ability to describe any part of the body in a specific stance is the anatomical position (Wiley, page 1)

· Use directional terms to describe the location of various body parts

Appendicular pertains to the extremities of limbs; cephalic depicts the head and mammary about the breast (Wiley, page 2)

· Distinguish between directional terms generally used to describe human body parts/position vs. four-legged animal body parts/position

Directional terms used to describe human body parts include; superior, which is used to describe how the head is excellent to the neck, inferior, which explains how the neck is subordinate to the head. The directional terms in animals include; quadruped which explains animals that walk on four legs, and caudal that describes the position of body structures near the tail area of an organism (Wiley, page 4)

· Distinguish between body landmarks considered to be anterior vs. posterior

Lips are considered to be anterior to the teeth whereas the teeth are considered to be posterior to the lips (Wiley, page 4)

· Identify what body parts regional terms are referring to

Geographical conditions divide the body into parts example; the axial region makes the central axis of the body it include the head, neck, and chest to name a few (Wiley, page 2)

· Describe and distinguish between the various body planes

Planes refer to the flat surfaces that divide the body organs so that internal structures are exposed. Sagittal planes dived body organs into right and left sections by passing vertically through the body, planes that pass through body organs, and divides them into equal parts. They are called midsagittal planes. Oblique planes pass through the body, creating angles forming diagonal sections. (Wiley, page 5)

· Identify the major body cavities and their subdivisions and be able to identify significant organs present in those cavities

Body cavities include the cranial cavity, which contains essential organs such as the brain, the vertebral consist of the spinal cord, the thoracic cavity consists of the ribs, and the sternum. The pericardial cavity surrounds the heart, whereas the pleural cavity surrounds the lung. (Wiley, page 16)

· Identify the divisions of the abdominopelvic cavity

The abdominopelvic hole is made up of two continuous cavities, the pelvic cavity and the abdominal cavity (Wiley, page 16)

· Describe the anatomy & function of serous membranes

Serous membranes are made of two layers a physical layer and a parietal layer. The physical layer is internal and covers organs, whereas the parietal layer covers the body wall. The two coats for a sac filled with fluid that prevents friction as body organs move. Thoracic serous membranes include the pleura which covers the lungs and the pericardium, which covers the heart. (Wiley, page 17)

· Define retroperitoneal

It is the space that occurs behind the peritoneum (Wiley, page 17)

· Identify organs protected by serous membranes

The heart and the lungs (Wiley, page 17)




Exam 1 Study Guide continued

III. Body Tissues

· Identify the four main tissue types

The four main tissue types include; epithelial tissue, connective tissue, muscle tissue and the nervous tissue (Wiley, page 17)

· Identify reasons why studying tissues is important

Histology helps people to understand cell behaviour and reproduction. It also helps people understand organ behaviour and function (AP lecture 3A slide 8)

· Distinguish between the structure, service, and location of the various tissue types (central tissues and subcategories) epithelial tissue is located in the skin, lining of the respiratory tract, lining of the stomach, kidneys, and glands. The main functions of epithelial tissue include absorption, protection, filtration, and secretion. Connective tissue is located everywhere in the body, and it’s the most abundant tissue. The function consists of connecting body parts, offering protection, support, and binding together other tissues. Muscle tissue is located in the skeletal muscles, cardiac muscles, hollow organs and in different muscle types functions include specialized in a way that it can contract to move. Nervous tissue is found in neurons, and the features are to insulate and support and protect neurons (AP lecture 3A slide8, 26, 44, and 49)

· Distinguish between endocrine and exocrine glands

Endocrine glands are the ductless glands, they secrete hormones, and their secretions are directly poured into the circulating blood and pour into the glans. Exocrine glands have ducts, and they secrete enzymes, mucous and other substances (AP lecture 3A slide 21 and 22)

· Distinguish between the different types of fibres found in connective tissue

Collagen, elastic and reticular fibres (AP lecture 3A slide 30)


IV. Tissue Growth and Repair

· Distinguish between the two types of tissue repair (regeneration and fibrosis)

Regeneration refers to the replacement of damaged tissue and refers to the same cells. Fibrosis is the repair of dense connective tissue and the formation of scar tissue. (AP lecture 2B (1) slide 6)

· Describe the stages of tissue repair

After tissue injury capillaries get permeable, then the granulation tissue forms, and eventually, epithelium regenerates (AP lecture 2B (1) slide 8)

· Describe the regeneration time of various tissues and factors affecting the regeneration of tissues

Epithelial tissues such as the skin, mucous membranes, and the fibrous connective tissues such as bones regenerate within a fairly successful time, whereas the skeletal, cardiac, and nervous tissue regenerates within a poor time frame (AP lecture 2B (1) slide 12).

· Describe tissue changes associated with aging

Tissues such as the epithelia become thinner, more prone to damage, skin loses elasticity, exocrine glands become less active, and the endocrine glands produce fewer hormones (AP lecture 2B (1) slide 16).

· Define neoplasm, hyperplasia, and atrophy

The tumor is the type of abnormal growth, whereas hyperplasia is the increase in cell numbers and enlargement of tissue. Atrophy is the decrease in size and loss of regular stimulation (AP lecture 2B (1) slide 18).


VI. Integumentary System

· Describe the functions of the skin

The skin protects organs, aids in the formation of vitamin D regulates body temperature and aids in excretion and absorption (Wiley, 83)

· Identify the cells that serve to protect the skin

Keratinocytes, Merkel cells, Langerhans cells, and melanocytes (Wiley, 84)

· Describe how the skin regulates body temperature

The surface has an immense blood supply that regulates the body’s temperatures (Wiley, 84)

· Describe the characteristics of the different layers of the skin

The cover has different layers; the epidermis is the outer layer consisting of the epithelial tissue, the dermis is a connective tissue that provides the epidermis with nutrients. The subcutaneous layer is found below the skin, and the hypodermis is the primary storage for adipose fabric (Wiley, 83)

· Describe the characteristics of the hypodermis

It is the deepest layer of the skin, stores fat, offers protection, and body temperature regulation (Wiley, 84)

· List the epidermal layers in order from deep to superficial or vice versa and describe the characteristics of each layer

Stratum Basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The stratum Basale is a single row of cells connected to the basement membrane, forms new keratinocytes. The Stratum spinosum forms a layer that contains thorn-like projections; in this layer, no dividing cells are present. The stratum lucidum has 3-5 rows of dead keratinocytes. The stratum corneum is a thick layer consisting of 25 to 30 or more rows of dead, squamous-shaped keratinocytes (Wiley, 84)

· Describe the role of melanocytes and melanin

Melanocytes are the cells responsible for producing melanin. Melanin protects the skin from harmful effects and UV light as well as colouring (Wiley, 84)

· Differentiate between the two dermal layers

The dermis consist of two regions called the reticular and papillary region. The papillary parts a thin layer of areolar connective tissue whereas the reticular parts the thicker and much more in-depth area of the dermis (Wiley, 84)

· Identify the three factors that contribute to skin colour

Epidermal pigmentation and dermal circulation (Wiley, 84)

· Differentiate between the various cutaneous glands

Sudoriferous glands secrete substances that regulate temperature and excretion facilitation. Apocrine glands are found in the genitals. They produce a more viscous secretion. Ceruminous glands are located in the ear that provides wax that prevents the entry of foreign substances in the ear. Mammary glands found in the breast produce milk. Sebaceous glands surround hair follicles producing oil (Wiley, 86)

· Describe the characteristics of hair (location, structures, colour, shape, size)

Hair has three layers of origin, namely; the cuticle, cortex, and medulla. The skin is the surface of hair that we see, the cells of cortex and medulla contain pigments that give hair its colour. Curly hair is flat in cross-section, wavy hair is oval, and straightened hair is round (Wiley, 86)

· Describe the structures of nails

Nails have a nail body, free edge, and a root. The nail body is the visible part, the free edge extends beyond the digit, and the heart is located within the skin. (Willey, 86)







VII. Homeostatic Imbalances of Skin

· Identify the defining characteristics of each of the following homeostatic imbalances of the skin

· Blister

Easily identified with a small pocket of body fluid. A feature of 2nd-degree burn.

· Decubitus ulcer

These are ulcers that develop on bony areas with little tissue to distribute the pressure.

· Cyanosis

A skin condition characterized by a bluish discolouration of the skin.

· Erythema

erythema is when there is redness on the skin caused by hyperemia.

· Pallor

A loss of colour on the eyelids and mucous membranes.

· Jaundice

Jaundice is a disorder that manifests in the yellowing of the skin and the white parts of the eye. Caused by accumulation of bilirubin.

· Hematoma

Characterized by the blood that escapes from the blood system. It can occur in different parts of the body.

· Acne

Acne leads to the outbreak of pimples caused by the overproduction of sebum.

· Athlete’s foot

It is a type of infection that occurs due to fungus.

· Boil

A painful bump filled with pus. A boil occurs when bacteria infects and inflames one or more of the hair follicles.

· Cold sore

Painful fluid-filled blisters caused by the herpes zoster virus. It can manifest on the lips, the vagina, or anywhere on the skin.

· Contact dermatitis

A red itchy rash caused by an allergen

· Impetigo

Painful sores that affect children and infants. Manifest on the face around the mouth.

· Psoriasis

A condition characterized by the formation of scales and red patches that sometimes painful. This occurs due to increased buildup of skin cells.

· Identify the life-threatening problems associated with burns

Bacterial infection, fluid loss, dangerously low body temperature, breathing problems, and bone and joint issues caused by injuries.

· Describe how fluid loss is estimated (Rule of Nines)

The rule of nines assesses the percentage of the burn and helps guide medical practitioners in making decisions concerning the transfer of the burn units. The burnt surface area can be estimated by the use of the multiples of nine.

· Describe how burns are classified

First-degree trauma affects the outer layer of the skin; the second-degree burn involves the epidermis and some parts of the lower skin layer; third-degree destroys the epidermis and dermis whereas the fourth-degree injury goes through deep layers of skin as well as tissues sometimes affecting bones and muscles.

· Differentiate between basal cell carcinoma, squamous cell carcinoma, and malignant melanoma

Basal cell carcinoma is characterized mostly by the occurrence of an open sore on the skin that does not heal quickly, squamous cell carcinoma is characterized by a bump that is usually rough or crusty and can bleed easily when scraped, and the malignant melanoma which is characterized by unusual moles with uneven borderlines and those that change in shape an color.

· Describe the ABCD rule

The ABCD rule is used to describe the warning signs of melanoma. A stands for asymmetrical that helps people identify whether moles have an irregular shape with two parts looking different. B stands for the border, is the border irregular or jagged. C stands for diameter is the mole more significant than the size of a pea. Letter E stands for has the mole changed during the past few weeks or months.

· Describe how skin changes as we age

The outer layer of the skin becomes thin, and the number of pigment-containing cells decreases. Aging skin looks paler, bright, with large pigment spots. The blood vessels of the dermis become less active, less oil is produced by the subcutaneous layer, and less sweat is produced, to name a few.

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