Chapter 20: Tissues & Organ Systems

Transcription

1 Chapter 20: Tissues & Organ Systems

2 The Importance of Homeostasis The maintenance of a relatively constant internal environment, i.e., homeostasis, is essential for life. Cellular conditions that need to be maintained within a narrow range include: Temperature ph concentrations of: minerals, nutrients, wastes

3 Negative Feedback Homeostasis is largely maintained by what is known as Negative Feedback: counteracting a change in body state to restore the original state e.g. sweating to cool an overheated body releasing insulin to lower blood sugar accelerated breathing, pulse to increase oxygen **various sensory systems in the body detect changes and trigger negative feedback responses**

4 Organization of the Animal Body Cells Tissues Organs Organ Systems

5 The 4 Basic Tissue Types All tissues in the animal body fall into one of 4 basic tissue types: Epithelial Tissue Connective Tissue Muscle Tissue Nerve Tissue

6 Epithelial Tissue Sheets of cells that line body surfaces, cavities: skin; digestive, urinary, reproductive tracts; vessels; glands Epithelial cells come in 3 basic shapes squamos (flattened) cuboidal (cube-shaped) columnar (elongated) and in single or multiple layers: simple or stratified epith.

7 Examples of Epithelial Tissue simple squamous epithelium (lung) stratified squamous epithelium (lining the esophagus) simple cuboidal epithelium (kidney) dead cells rapidly dividing cells Colorized SEM simple columnar epithelium (intestine) stratified squamous epithelium (human skin)

8 Connective Tissue Tissue that supports, binds, fills or provides structure. contains few cells, mostly extracellular matrix (ECM) Connective Tissue (CT) comes in 3 basic types: Loose CT underlies epithelium, loosely woven fibers, gel-like Fibrous or Dense CT densely packed fibers as in tendons & ligaments Specialized CT bone, cartilage, blood & lymph, adipose (fat) tissue

9 Examples of Connective Tissue Fat droplets adipose tissue Cartilageforming cells Matrix Cell nucleus cartilage (end of a bone) fibrous connective tissue (tendon) Collagen fibers loose connective tissue (under the skin) White blood cells Red blood cell Plasma blood bone Central canal Matrix Boneforming cells

10 Muscle Tissue Made of cells that contract, comes in 3 types: Skeletal Muscle (striated, voluntary moves skeleton) Cardiac Muscle (striated, involuntary heartbeat) Smooth Muscle (unstriated, involuntary visceral org., vessels) Unit of muscle contraction Muscle fiber Muscle fiber Nucleus Junction between two cells Nucleus cardiac muscle Muscle fiber Nucleus skeletal muscle smooth muscle

11 Nerve Tissue Tissue that transmits electrical signals. neuron Contains 2 basic cell types: Neurons cells that generate, transmit electrical signals Glial cells (glia) metabolic support, insulation for neurons

12 Organs and Organ Systems Organs = multiple tissues that comprise a physically & functionally distinct structure Organ systems = multiple organs that work together to perform a common function each tissue and organ has a distinct role e.g. Integumentary System (skin, nails, etc) skin, nails, hair each have different roles each contains multiple tissues (epithelium, connective tissue, muscle, nerve) with diff. roles

13 Organs are made of all Tissue Types Lumen Small intestine (cut open) epithelial tissue (columnar epithelium) Lumen connective tissue smooth muscle tissue (2 layers) connective tissue epithelial tissue

14 10 Major Organ Systems (11 if you count the Integumentary System) The Circulatory System (blood & vessels, heart) nutrient & waste transport temperature control ph balance movement of cells, hormones Lymphatic/Immune System (lymph & vessels, lymphocytes) fluid balance, transport fat transport immune responses

15 Organ Systems cont d The Endocrine System (endocrine glands) hormone production physiological control The Nervous System (brain, spinal cord, nerves) internal, external sensation behavioral control physiological control

16 The Digestive System (esophagus, stomach, liver, intestines, pancreas) food breakdown, absorption waste disposal The Urinary System (kidneys, bladder) blood-borne waste disposal salt & water homeostasis The Respiratory System (pharynx, trachea, lungs) gas exchange ph balance

17 The Muscular System (all 3 muscle types) movement of skeleton movement in hollow organs heartbeat The Skeletal System (bones, cartilage, tendons ) structural support blood production calcium, phosph. storage The Reproductive System (ovaries, uterus, testes ) gamete, production hormone production nurturing offspring

18 homeostasis Key Terms for Chapter 20 epithelium squamous, cuboidal, columnar simple & stratified connective tissue loose, fibrous, specialized skeletal, smooth & cardiac muscle neurons & glial cells Relevant Review Questions: 2-14

19 Chapters 21-23, 25: Organ Systems of the Body 1. Circulatory System 2. Respiratory System 3. Digestive System 4. Urinary System

20 1. The Circulatory System

21 immune protection (antibodies, white blood cells) Organs of the Circulatory System Heart pumps the blood Blood vessels veins, arteries, capillaries Blood red & white blood cells, blood plasma (we ll also look at lymph and lymphatic vessels) Roles of the Circulatory System deliver O 2, remove CO 2 transport nutrients, wastes, hormones regulate temperature & ph

22 Vertebrate Circulation Fish have a 2 chambered heart Reptiles & amphibians have a 3 chambered heart Mammals & birds have a heart with 4 chambers

23 right ventricle left ventricle The Human Heart right atrium left atrium semilunar valve semilunar valve atrioventricular (AV) valve atrioventricular (AV) valve

24 The Cardiac Cycle oxygenated vs deoxygenated 1. Atria contract, forcing blood from right atrium & left atrium into ventricles 2. Ventricles contract, forcing blood into aorta (fr. LV) and pulmonary artery (fr. RV) systole 3. Atria & ventricles relax (diastole), cycle repeats

25 superior vena cava 8 capillaries of head, chest, and arms pulmonary artery capillaries of right lung 9 aorta pulmonary artery capillaries of left lung pulmonary vein pulmonary vein right atrium 9 left atrium right ventricle aorta left ventricle inferior vena cava Blood Circulation 8 capillaries of abdominal region and legs

26 Control of the Heartbeat The synchronous contraction of cardiac muscle cells is controlled by the sinoatrial (SA) & atrioventricular (AV) nodes. ea beat starts at the SA node, stimulates AV node (delayed) Pacemaker (SA node) AV node Specialized muscle fibers Right ventricle Apex 4 ECG

27 Oxygen Transport Oxygen is transported by red blood cells (RBCs) aka erythrocytes don t have a nucleus! vast majority of blood cells (~99%) are RBCs Oxygen binds to hemoglobin in RBCs each hemoglobin molecule binds 8 O 2 vast majority of protein in RBCs is hemoglobin

28 Other Blood Cells Blood also contains: Platelets essential for blood clotting pinch off from cells in bone marrow called megakaryocytes White Blood Cells collective term for all cells of immune system B cells, T cells, monocytes, neutrophils

29 Blood Vasculature Arteries, arterioles: conduct blood flow away from the heart usually oxygenated blood Veins, venules: conduct blood flow toward the heart usu. deoxygenated blood Capillaries: smallest vessels where exchange occurs

30 Capillaries Unlike larger vessels, capillary walls are only 1 cell thick, barely wide enough for RBCs to pass through allows diffusion of gases, nutrients, wastes between blood & tissues some fluid (plasma) leaks out as well

31 The Lymphatic System A vascular system distinct from the circulatory system conducts fluid leaked from the blood called lymph returned to blood at vena cava lymph is filtered through structures called lymph nodes full of immune cells, important part of the immune response also transports fats from digestion in small intestine

32 Lymphatic Vessels Fluid leaked from capillaries is taken up by lymph capillaries lymph is conducted into larger lymphatic vessels lymph passes through lymph nodes before being dumped into the blood at the vena cava

33 2. The Respiratory System

34 The Respiratory System Respiratory System function : facilitate O 2 uptake, waste CO 2 removal

35 Respiratory System Organs Nasal Cavity Pharynx warms & moistens air passage for air, food/water Larynx Epiglottis Trachea Lungs Diaphragm vocal chords; where air, food separate blocks airway when swallowing connects airway to lungs site of gas exchange muscle used for inhaling

36 Inhalation & Exhalation Rib cage expands as rib muscles contract air inhaled Rib cage gets smaller as rib muscles relax air exhaled lung diaphragm Diaphragm contracts (moves down) Inhalation Diaphragm relaxes (moves up) Exhalation

37 The Lungs The bronchi of the lungs branch into smaller and smaller bronchioles which terminate in alveoli. alveoli are the sites of gas exchange arrangement maximizes the surface area for gas exchange

38 Gas Exchange in the Alveoli O 2 and CO 2 simply diffuse from higher to lower concentration across the capillary, alveolar epithelia O 2 is more concentrated in the lungs than in the blood CO 2 is more concentrated in the blood than in the lungs *situation reversed in body tissues*

39 Summary of Gas Exchange lungs Deoxygenated blood from tissues returns to the right atrium & ventricle of the heart which pumps it to the lungs. In the alveoli of the lungs blood is oxygenated and flows back to the left atrium & ventricle of the heart, from which it is pumped back to the body. tissues

40 3. The Digestive System

41 Digestive System Functions 1) Digest food and absorb nutrients mechanical breakdown physical breakdown of food into smaller particles chemical digestion breakdown of large molecules (polymers) into smaller ones (monomers) absorption transfer of digested material into blood & lymph 2) Waste removal undigested material & waste from liver

42 Organs of the Digestive System Digestive Tract mouth pharynx esophagus stomach small intestine large intestine Accessory Organs liver gall bladder pancreas

43 Early Digestion Mouth & Pharynx chewing (mastication) of food, mixing with saliva swallowing of food bolus Bolus of food Muscles contract, constricting passageway and pushing bolus down starch digestion via amylase Muscles contract Muscles relax Muscles relax, allowing passageway to open Esophagus muscular tube conducting food bolus from pharynx to stomach Stomach Stomach mechanically churns food adds pepsin (digests protein) and HCl (kills microbes, activates pepsin) Muscles relax Muscles contract

44 Completion of Digestion Small Intestine 3 sections: duodenum > jejunum > ileum digestion is completed in the duodenum absorption of nutrients Pancreas secretes pancreatic juice (enzymes, bicarbonate) to complete digestion Liver & Gall Bladder bile from liver added to duodenum via gall bladder bile helps emulsify fats for better digestion

45 Nutrient Absorption Nutrients are absorbed throughout small intestine. nutrients are transferred to the blood or the lymph (fats) Vein with blood en route to the liver nutrient absorption Lumen of Intestine nutrient absorption into epithelial cells microvilli muscle layers large circular folds villi lumen nutrient absorption epithelial cells blood capillaries lymph vessel amino acids and sugars blood lymph fatty acids and glycerol fats Epithelial Cells Villi Intestinal Wall

46 Folds, Villi & Microvilli Folds in the intestinal wall as well as villi & microvilli greatly increase surface area for nutrient absorption. villi are multicellular finger-like projections microvilli are projections on individual cells

47 Waste Removal Large Intestine: cecum > colon > rectum absorption of water, minerals, vitamins compaction, elimination of waste (undigested material, fiber, bacteria) Large intestine (colon) houses a variety of beneficial bacteria (aka probiotics ) Sphincter End of small intestine Anus Small intestine Rectum ***bacteria need to be kept OUT of small intestine*** Cecum Appendix Nutrient flow

48 4. The Urinary System

49 The Urinary System Kidneys removal of waste, excess in blood Ureters conduct urine from kidneys to bladder Bladder holds, expels urine Urethra conducts urine from bladder out

50 The Kidney Organized into functional units called nephrons

51 glomerulus Nephron Structure

52 Filtration in the Kidney 1. Dissolved substances leave the blood in the glomerulus, enter glomerular capsule > tubule 2. Needed H 2 0, salt, nutrients reabsorbed from tubule tubule 3 *maintains ph, salt & water homeostasis* glomerulus 3. Additional wastes added to urine 4. H 2 O reclaimed

53 Water & Salt Homeostasis Antidiuretic Hormone (ADH) regulates water resorption in the kidneys: released by the pituitary gland sensors in brain and heart regulate ADH release increases permeability of kidney tubules, greater water resorption Aldosterone released from the adrenal cortex regulates salt levels: stimulates retention of sodium ions (Na + ), excretion of potassium (K + ) in kidneys

54 Relevant Review Questions: Ch. 21: 1 Ch. 22: 1, 2, 5, 7 Ch. 23: 1, 2, 4, 5 Ch. 25: 2, 4 Key Terms for Chapters & 25 atrium, ventricle, aorta, vena cava sinoatrial, atrioventricular nodes hemoglobin, white blood cells, platelets arteries, arterioles, veins, venules, capillaries lymph, lymph nodes pharynx, larynx, epiglottis, diaphragm, alveoli villi, microvilli, nephron, glomerulus, tubule