Comprehensive Study Guide: Animal Nutrition & Chemical Signals in Animals

A comprehensive set of flashcards covering key concepts in animal nutrition and chemical signaling.

Nutritional Requirements

Chemical energy for ATP production; carbon-containing compounds for building molecules; animals are heterotrophs that must obtain nutrients from other organisms.

Steps of Nutrition

1. Ingestion: taking food into digestive tract. 2. Digestion: breaking food into smaller components. 3. Absorption: uptake of ions/molecules across digestive epithelium. 4. Elimination: removal of waste.

Essential Nutrients

Nutrients that must be obtained from diet, including essential amino acids, essential fatty acids, vitamins, and minerals.

Digestive Tract Types

Incomplete digestive tract (one opening) like gastrovascular cavities (e.g., Hydra) and complete digestive tract (two openings: mouth to anus) that allows compartmentalization of processes.

Mouth Functions

Mechanical digestion through chewing and chemical digestion by salivary amylase breaking starch into maltose and lingual lipase initiating lipid digestion.

Stomach Function

Mechanical digestion through churning; chemical digestion of proteins with HCl and pepsin.

Ulcers

Caused by Helicobacter pylori, not just excess acid.

Small Intestine Functions

Major site for chemical digestion and absorption; receives secretions from pancreas (enzymes) and liver (bile salts).

Glucose Homeostasis

Insulin decreases blood glucose by increasing uptake and stimulating glycogen formation; glucagon increases blood glucose by breaking down glycogen.

Chemical Signals

Hormones are chemical signals in body fluids; act at low concentrations but have significant effects.

Five Categories of Chemical Signals

1. Autocrine: acts on same cell. 2. Paracrine: acts on nearby cells. 3. Endocrine: carried by blood to distant cells. 4. Neural: neurotransmitters for fast signaling. 5. Neuroendocrine: released by neurons into blood.

Endocrine System Anatomy

Includes hypothalamus (releases regulatory hormones), pituitary gland (stores/releases hormones), thyroid, adrenal glands, pancreas, and gonads.

Hormonal Feedback Mechanisms

Negative feedback loops maintain hormone levels, while positive feedback loops amplify hormone production in certain situations.

Asexual Reproduction

Involves mitosis to produce identical offspring, with methods such as budding and fission.

Fertilization Process Steps

1. Sperm reaches egg. 2. Membrane fusion. 3. Nuclei fuse to form a zygote.

Embryonic Development Stages

1. Cleavage: rapid division. 2. Blastula: ball of cells. 3. Gastrulation: forms three germ layers.

Germ Layers

Ectoderm (skin, nervous system), mesoderm (muscles, organs), endoderm (digestive lining).

Menstrual Cycle Phases

Follicular phase (estrogen increase), ovulation (egg release), luteal phase (progesterone increase).

Puberty Control Pathway

Hypothalamus releases GnRH → Pituitary releases LH & FSH → Gonads produce sex hormones.

Action Potentials

Electrical signals along neurons. Rapid and short-lived.

Difference Between Nervous and Endocrine Systems

Nervous system: fast, electrical signals for short-term responses; Endocrine system: slow, hormonal signals for long-lasting effects.